Đề thi giữa kì 2 Tiếng Anh 11 Thí điểm (có đáp án - Đề 4)

  • 1Làm xong biết đáp án, phương pháp giải chi tiết.
  • 2Học sinh có thể hỏi và trao đổi lại nếu không hiểu.
  • 3Xem lại lý thuyết, lưu bài tập và note lại các chú ý
  • 4Biết điểm yếu và có hướng giải pháp cải thiện

Câu 1:

Mark the letter A, B, C. or D on your answer sheet to indicate the most suitable response to each of the following sentences

Mary: “Would you mind if I use your computer for an hour?” Tony:"_____”

A. Not at all. I've finished my job

B. Yes, you can use it

C. Of course not. I still need it now

D. Yes. It’s all right.

Câu 2:

Mark the letter A, B, C. or D on your answer sheet to indicate the most suitable response to each of the following sentences

Tom: "Do you think it's going to rain?” - Trump: “_______”

A. I don't hope so

B. I don't hope so

C. I hope not

D. I think not

Câu 3:

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following sentences

My father is in_______ of 30 engineers and 80 workers.

A. pressure

B. leadership

C. impression

D. charge

Câu 4:

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following sentences

 ________taken my parents’ advice, I wouldn't be a teacher now.

A. Had I

B. If I hadn’t

C. If I would have

D. Could I have

Câu 5:

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following sentences

He is decorating his house ___________selling it.

A. in order to

B. with a view to

C. in order that

D. so that

Câu 6:

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following sentences

On_________ he had won the first prize in the competition, he cried out with joy.

A. being told

B. having cold

C. telling

D. saying

Câu 7:

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following sentences

By the end of this March he ______here for 20 years.

A. has been living

B. will live

C. will have been living

D. will be living

Câu 8:

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following sentences

The government is aiming___________ 50% reduction______ unemployment

A. at /of

B. in/ to

C. on/ at

D. at /in

Câu 9:

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following sentences

I am not going to study French and__________

A. so is he

B. neither is he

C. he isn’t too

D. either isn’t he

Câu 10:

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following sentences

Many young people in rural areas don`t want to spend their lives on the farm like______ parents.

A. weather-beaten

B. up-to-date

C. long-term

D. wide-range

Câu 11:

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following sentences

I believe nobody survived the plane crash_________

A. did I 

B. didn’t they

C. did they

D. did he

Câu 12:

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following sentences

________they arrived __________they were told to go back.

A. No sooner/when

B. Scarcely had/when

C. Scarcely/when

D. Hardly/when

Câu 13:

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following sentences

Yuri Gagarin was the first person __________into space

A. has traveled

B. traveling

C. traveled

D. to travel

Câu 14:

Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following sentences

To preserve that _________, it was necessary to preserve the people that had created it.

A. civilize

B. civilization

C. civility

D. civil

Câu 15:

Mark the letter A, B, C, or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions

A. kite

B. bite

C. favorite

D. quite

Câu 16:

Mark the letter A, B, C, or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions

A. coached

B. needed

C. wanted

D. beloved

Câu 17:

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks

Schools in the United States have not always had a large number of libraries. As recently as 1958 about half of the public schools in the United States had no libraries at all. The (17)_______of public school libraries increased dramatically when the federal government passed the Elementary and Secondary Education Act of 1965, which provided funds for school districts to improve their education programs and facilities, including their libraries. (18) _______, many educators claim that since the legislation was passed federal spending has not increased sufficiently to meet the rising cost of new library technologies such as computer databases and Internet access.

Because the federal government provides only limited funds to schools, individual school districts (19)______ on funds from local property taxes to meet the vast majority of public schools tend to reflect the financial capabilities of the communities in which they are located. Districts in wealthy suburbs often have fully staffed libraries (20)________ abundant resources, spacious facilities, and curricular and instructional support. In (21) __________school districts in many poor areas house their libraries in ordinary classrooms or in small rooms. The libraries in such areas are generally staffed by volunteers, who organize and maintain books that are often out-of-date, irrelevant, or damaged.

Question 17

A. digit

B. amount

C. number

D. numeral

 

Câu 18:

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks

Schools in the United States have not always had a large number of libraries. As recently as 1958 about half of the public schools in the United States had no libraries at all. The (17)_______of public school libraries increased dramatically when the federal government passed the Elementary and Secondary Education Act of 1965, which provided funds for school districts to improve their education programs and facilities, including their libraries. (18) _______, many educators claim that since the legislation was passed federal spending has not increased sufficiently to meet the rising cost of new library technologies such as computer databases and Internet access.

Because the federal government provides only limited funds to schools, individual school districts (19)______ on funds from local property taxes to meet the vast majority of public schools tend to reflect the financial capabilities of the communities in which they are located. Districts in wealthy suburbs often have fully staffed libraries (20)________ abundant resources, spacious facilities, and curricular and instructional support. In (21) __________school districts in many poor areas house their libraries in ordinary classrooms or in small rooms. The libraries in such areas are generally staffed by volunteers, who organize and maintain books that are often out-of-date, irrelevant, or damaged.

Question 18

A. Otherwise

B. Therefore

C. Consequently

D. Nevertheless

Câu 19:

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks

Schools in the United States have not always had a large number of libraries. As recently as 1958 about half of the public schools in the United States had no libraries at all. The (17)_______of public school libraries increased dramatically when the federal government passed the Elementary and Secondary Education Act of 1965, which provided funds for school districts to improve their education programs and facilities, including their libraries. (18) _______, many educators claim that since the legislation was passed federal spending has not increased sufficiently to meet the rising cost of new library technologies such as computer databases and Internet access.

Because the federal government provides only limited funds to schools, individual school districts (19)______ on funds from local property taxes to meet the vast majority of public schools tend to reflect the financial capabilities of the communities in which they are located. Districts in wealthy suburbs often have fully staffed libraries (20)________ abundant resources, spacious facilities, and curricular and instructional support. In (21) __________school districts in many poor areas house their libraries in ordinary classrooms or in small rooms. The libraries in such areas are generally staffed by volunteers, who organize and maintain books that are often out-of-date, irrelevant, or damaged.

Question 19

A. rely

B. come

C. go

D. stay

Câu 20:

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks

Schools in the United States have not always had a large number of libraries. As recently as 1958 about half of the public schools in the United States had no libraries at all. The (17)_______of public school libraries increased dramatically when the federal government passed the Elementary and Secondary Education Act of 1965, which provided funds for school districts to improve their education programs and facilities, including their libraries. (18) _______, many educators claim that since the legislation was passed federal spending has not increased sufficiently to meet the rising cost of new library technologies such as computer databases and Internet access.

Because the federal government provides only limited funds to schools, individual school districts (19)______ on funds from local property taxes to meet the vast majority of public schools tend to reflect the financial capabilities of the communities in which they are located. Districts in wealthy suburbs often have fully staffed libraries (20)________ abundant resources, spacious facilities, and curricular and instructional support. In (21) __________school districts in many poor areas house their libraries in ordinary classrooms or in small rooms. The libraries in such areas are generally staffed by volunteers, who organize and maintain books that are often out-of-date, irrelevant, or damaged.

Question 20

A. for

B. with

C. on

D. by

Câu 21:

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks

Schools in the United States have not always had a large number of libraries. As recently as 1958 about half of the public schools in the United States had no libraries at all. The (17)_______of public school libraries increased dramatically when the federal government passed the Elementary and Secondary Education Act of 1965, which provided funds for school districts to improve their education programs and facilities, including their libraries. (18) _______, many educators claim that since the legislation was passed federal spending has not increased sufficiently to meet the rising cost of new library technologies such as computer databases and Internet access.

Because the federal government provides only limited funds to schools, individual school districts (19)______ on funds from local property taxes to meet the vast majority of public schools tend to reflect the financial capabilities of the communities in which they are located. Districts in wealthy suburbs often have fully staffed libraries (20)________ abundant resources, spacious facilities, and curricular and instructional support. In (21) __________school districts in many poor areas house their libraries in ordinary classrooms or in small rooms. The libraries in such areas are generally staffed by volunteers, who organize and maintain books that are often out-of-date, irrelevant, or damaged.

Question 21

A. conflict

B. converse

C. contrary

D. contrast

Câu 22:

Mark the letter A, B, C, or D on your answer answer sheet to indicate the underlined part that needs correction in each of the questions

By the time Robert will finish writing the first draft of his paper, most of the other students will have completed their final draft

A. will finish

B. writing

C. most

D. their

Câu 23:

Mark the letter A, B, C, or D on your answer answer sheet to indicate the underlined part that needs correction in each of the questions

The team leader demanded from his team members a serious attitude towards work, a good team spirit, and that they work hard

A. team leader

B. his team members

C. attitude towards work

D. and that they work hard

Câu 24:

Mark the letter A, B, C, or D on your answer answer sheet to indicate the underlined part that needs correction in each of the questions

Each of the beautiful cars in the shop was quickly sold to their owner

A. Each

B. cars

C. quickly

D. their

Câu 25:

Read the following passage and mark the letter A, B, C, or D on your answer answer to each of the questions

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions. Many of more important air pollutants such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentrations of these pollutants were altered by various chemical reactions; they became components in biogeochemical cycle. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil on a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In this localized regions, human output may be dominant and may temporarily overload the natural purification scheme of the cycle. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, as a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

What does the passage mainly discuss?

A. The economic impact of air pollution

B. What constitutes an air pollutant

C. How much harm air pollutants can cause

D. The effects of compounds added to the atmosphere

Câu 26:

Read the following passage and mark the letter A, B, C, or D on your answer answer to each of the questions

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions. Many of more important air pollutants such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentrations of these pollutants were altered by various chemical reactions; they became components in biogeochemical cycle. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil on a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In this localized regions, human output may be dominant and may temporarily overload the natural purification scheme of the cycle. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, as a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

The word "adversely" is closest in meaning to

A. negatively

B. quickly

C. admittedly

D. considerably

Câu 27:

Read the following passage and mark the letter A, B, C, or D on your answer answer to each of the questions

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions. Many of more important air pollutants such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentrations of these pollutants were altered by various chemical reactions; they became components in biogeochemical cycle. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil on a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In this localized regions, human output may be dominant and may temporarily overload the natural purification scheme of the cycle. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, as a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

It can be inferred from the first paragraph that

A. water vapor is an air pollutant in localized areas

B. most air pollutants today can be seen or smelled

C. the definition of air pollution will continue to change

D. a substance becomes an air pollutant only in cities

Câu 28:

Read the following passage and mark the letter A, B, C, or D on your answer answer to each of the questions

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions. Many of more important air pollutants such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentrations of these pollutants were altered by various chemical reactions; they became components in biogeochemical cycle. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil on a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In this localized regions, human output may be dominant and may temporarily overload the natural purification scheme of the cycle. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, as a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

The word "these" in the second paragraph is closest in meaning to

A. the various chemical reactions

B. the pollutants from the developing Earth

C. the compounds mover to the water or soil

D. the components in biogeochemical cycles

Câu 29:

Read the following passage and mark the letter A, B, C, or D on your answer answer to each of the questions

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions. Many of more important air pollutants such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentrations of these pollutants were altered by various chemical reactions; they became components in biogeochemical cycle. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil on a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In this localized regions, human output may be dominant and may temporarily overload the natural purification scheme of the cycle. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, as a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

For which of the following reasons can natural pollutants play an important role in controlling air pollution?

A. They function as part of a purification process.

B. They occur in greater quantities than other pollutants.

C. They are less harmful to living beings than are other pollutants.

D. They have existed since the Earth developed.

Câu 30:

Read the following passage and mark the letter A, B, C, or D on your answer answer to each of the questions

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions. Many of more important air pollutants such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentrations of these pollutants were altered by various chemical reactions; they became components in biogeochemical cycle. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil on a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In this localized regions, human output may be dominant and may temporarily overload the natural purification scheme of the cycle. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, as a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

The word "localized” is closest in meaning to

A. specified

B. circled

C. surrounded

D. encircled

Câu 31:

Read the following passage and mark the letter A, B, C, or D on your answer answer to each of the questions

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions. Many of more important air pollutants such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentrations of these pollutants were altered by various chemical reactions; they became components in biogeochemical cycle. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil on a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In this localized regions, human output may be dominant and may temporarily overload the natural purification scheme of the cycle. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, as a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

The word "detectable" in the third paragraph is closest in meaning to

A. beneficial

B. special

C. measurable

D. separable

Câu 32:

Mark the letter A, B, C, or D on your answer sheet to indicate the semtence that best combines each pair of sentences in the following questions

People should not throw rubbish in the park. People should not cut down the trees in the park.

A. People should both cut down the trees and throw rubbish in the park

B. People should neither throw rubbish nor cut down the trees in the park.

C. People should throw rubbish and cut down the trees in the park.

D. People should either throw rubbish or cut down the trees in the park

Câu 33:

Read the following passage and mark the letter A, B, C, or D on your answer answer to each of the questions

An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled – a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions. Many of more important air pollutants such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentrations of these pollutants were altered by various chemical reactions; they became components in biogeochemical cycle. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil on a global basis, nature's output of these compounds dwarfs that resulting from human activities.

However, human production usually occurs in a localized area, such as a city. In this localized regions, human output may be dominant and may temporarily overload the natural purification scheme of the cycle. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, as a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm.

The team reached the top of the mountain. The team spent a night there.

A. The team had not only reached the top of the mountain, but they spend a night there as well.

B. Not only did the team reach the top of the mountain but they also spent a night there

C. Not only did the team reach the top of the mountain but they also spent a night there as well

D. The team both reach the top of the mountain but they also spent a night there