There_______ a new law to protect endanggered species if we don't want them to disappear from the earth
A. must to be B. needs to be C. might be D. may be
Mark the letter a, B, C, or D on your answer sheet to indicate the sentence that is closest meaning to each of the following questions or indicate the correct answer to each of them from 1 to 7
It is estimated that over 99 percent of all species that ever existed have become extinct. What causes extinction? When a species is no longer adapted to a changed environment, it may perish. The exact causes of a species’ death vary from situation to situation. Rapid ecological change may render an environment hostile to a species. For example, temperatures may change and a species may not be able to adapt. Food resources may be affected by environmental changes, which will then cause problems for a species requiring these resources. Other species may become better adapted to an environment, resulting in competition and, ultimately, in the death of a species.
The fossil record reveals that extinction has occurred throughout the history of Earth. Recent analyses have also revealed that on some occasions many species become extinct at the same time- a mass extinction. One of the best- known examples of mass extinction occurred 65 million years ago with the demise of dinosaurs and many other forms of life. Perhaps the largest mass extinction was the one that occurred 225 million years ago, when appropriately 95 percent of all species died. Mass extinction can be caused by a relatively rapid change in the environment and can be worsened by the close interrelationship of many species. If, for example, something were to happen to destroy much of the plankton in the oceans, then the oxygen content of Earth would drop, affection even organisms not living in the ocean. Such a change would probably lead to a mass extinction.
One interesting, and controversial, finding is that extinctions during the past 250 million years have tended to be more intense every 26 million years. This periodic extinction might be due to intersection of the Earth’s orbit with a cloud of comets, but this theory is purely speculative. Some researchers have also speculated that extinction may often be random. That is, certain species may be eliminated and others may survive for no particular reason. A species’ survival may have nothing to do with its ability to adapt. If so, some of evolutionary history may reflect a sequence of essentially random events.
According to paragraph 2, evidence from fossil suggests that
A. extinction of species has occurred from time to time throughout Earth’s history
B. dinosaurs became extinct much earlier than scientists originally believed
C. extinctions on Earth have generally been massive
D. there has been only one mass extinction in Earth’s history
Đáp án A
Theo đoạn 2, bằng chứng từ hóa thạch chỉ ra rằng:
A. Sự tuyệt chủng của các loài đã xảy ra liên tục trong suốt tiến trình lịch sử Trái Đất.
B. Khủng long đã tuyệt chủng sớm hơn nhiều so với các nhà khoa học tin rằng.
C. Sự tuyệt chủng trên trái đất nhìn chung là mang tính hàng loạt.
D. Chỉ có duy nhất 1 lần sự tuyệt chủng hàng loạt diễn ra trong lịch sử Trái Đất.
Dẫn chứng ở câu đầu tiên đoạn 2: “The fossil record reveals that extinction has occurred throughout the history of Earth”- ( Ghi nhận về hóa thạch tiết lộ rằng sự tuyệt chủng đã xảy ra trong suốt tiến trình lịch sử Trái Đất)
Mark the letter a, B, C, or D on your answer sheet to indicate the sentence that is closest meaning to each of the following questions or indicate the correct answer to each of them from 1 to 7
It is estimated that over 99 percent of all species that ever existed have become extinct. What causes extinction? When a species is no longer adapted to a changed environment, it may perish. The exact causes of a species’ death vary from situation to situation. Rapid ecological change may render an environment hostile to a species. For example, temperatures may change and a species may not be able to adapt. Food resources may be affected by environmental changes, which will then cause problems for a species requiring these resources. Other species may become better adapted to an environment, resulting in competition and, ultimately, in the death of a species.
The fossil record reveals that extinction has occurred throughout the history of Earth. Recent analyses have also revealed that on some occasions many species become extinct at the same time- a mass extinction. One of the best- known examples of mass extinction occurred 65 million years ago with the demise of dinosaurs and many other forms of life. Perhaps the largest mass extinction was the one that occurred 225 million years ago, when appropriately 95 percent of all species died. Mass extinction can be caused by a relatively rapid change in the environment and can be worsened by the close interrelationship of many species. If, for example, something were to happen to destroy much of the plankton in the oceans, then the oxygen content of Earth would drop, affection even organisms not living in the ocean. Such a change would probably lead to a mass extinction.
One interesting, and controversial, finding is that extinctions during the past 250 million years have tended to be more intense every 26 million years. This periodic extinction might be due to intersection of the Earth’s orbit with a cloud of comets, but this theory is purely speculative. Some researchers have also speculated that extinction may often be random. That is, certain species may be eliminated and others may survive for no particular reason. A species’ survival may have nothing to do with its ability to adapt. If so, some of evolutionary history may reflect a sequence of essentially random events.
The underlined word “demise” is closest in meaning to
A. help
B. change
C. death
D. recovery
Đáp án C
Đáp án C. demise (n) = death: cái chết.
Các đáp án còn lại:
A. help (n+v): giúp đỡ.
B. change (n+v): thay đổi.
D. recovery (n): sự khôi phục, sự phục hồi
Mark the letter a, B, C, or D on your answer sheet to indicate the sentence that is closest meaning to each of the following questions or indicate the correct answer to each of them from 1 to 7
It is estimated that over 99 percent of all species that ever existed have become extinct. What causes extinction? When a species is no longer adapted to a changed environment, it may perish. The exact causes of a species’ death vary from situation to situation. Rapid ecological change may render an environment hostile to a species. For example, temperatures may change and a species may not be able to adapt. Food resources may be affected by environmental changes, which will then cause problems for a species requiring these resources. Other species may become better adapted to an environment, resulting in competition and, ultimately, in the death of a species.
The fossil record reveals that extinction has occurred throughout the history of Earth. Recent analyses have also revealed that on some occasions many species become extinct at the same time- a mass extinction. One of the best- known examples of mass extinction occurred 65 million years ago with the demise of dinosaurs and many other forms of life. Perhaps the largest mass extinction was the one that occurred 225 million years ago, when appropriately 95 percent of all species died. Mass extinction can be caused by a relatively rapid change in the environment and can be worsened by the close interrelationship of many species. If, for example, something were to happen to destroy much of the plankton in the oceans, then the oxygen content of Earth would drop, affection even organisms not living in the ocean. Such a change would probably lead to a mass extinction.
One interesting, and controversial, finding is that extinctions during the past 250 million years have tended to be more intense every 26 million years. This periodic extinction might be due to intersection of the Earth’s orbit with a cloud of comets, but this theory is purely speculative. Some researchers have also speculated that extinction may often be random. That is, certain species may be eliminated and others may survive for no particular reason. A species’ survival may have nothing to do with its ability to adapt. If so, some of evolutionary history may reflect a sequence of essentially random events.
The underlined word “ultimately” is closest in meaning to
A. eventually
B. unfortunately
C. dramatically
D. exceptionally
Đáp án A
Đáp án A. ultimately = eventually: cuối cùng, rốt cục thì.
Các đáp án còn lại:
B. không may mắn.
C. đột ngột.
D. cá biệt, khác thường.
a) You ........if you work with chemical ( must )
b) If you feel tied, you ......... ( ougth to )
c) You........ if you want to be healthy ( should)
d) He......... if he wants to be good at English ( should)
e) If you want to go to the cinema , you........( must)
f) If we suffer from a disease, we..........( must )
a) You ...must be careful .....if you work with chemical ( must )
b) If you feel tied, you .....ougth to go to bed early.... ( ougth to )
c) You...should eat more vegetable..... if you want to be healthy ( should)
d) He.....should learn harder.... if he wants to be good at English ( should)
e) If you want to go to the cinema , you..must finish your homework......( must)
f) If we suffer from a disease, we....must go to the doctor......( must )
I. Circle A, B, C or D to choose the words with different stress
1. A. pursue B. enrol C,.equal D. repeat
2. A. lonely B. alone C. major D. famous
3. A. income B. workforce C. nature Dmature
4. A. knowledge B. challenge C .enjoy D. labor
5. A. pretty B. freedom C. happen D. begin
II. Give the correct form of the verb in brackets in the passive voice
1. A new monitor will be selected (will/select) by the members of the class next semester.
2. Information (can/find) due to the aid of the Internet.
3. If you want your car to be in good condition, it (must/service) frequently.
4. Students (not/should/give) everything about the subjects by their lecturers. They need to be creative and
discover new knowledge.
5. This house (must/sell) within 2 months.
6. When people have experienced something terrible, funny things (can/do).
7. A valid work permit (must/hold) by all employees.
8. Advice from the experts (should/take) by the government before making the new law.
9. Cultural differences (ought to/consider) by companies when engaging in business with overseas
organizations.
10. Some changes to our lives (must/ make) if we want to reduce pollution
III. Change the following sentences into passive voice.
1. You should finish the work before you leave.
_________________________________________________.
2. You can serve this wine with chicken or fish.
_________________________________________________
3.
We will elect a new government next year.
_________________________________________________
4. They might give him an award.
_________________________________________________
5. You must give students enough time to finish.
_________________________________________________.
6. You should keep flowers in a warm sunny place.
________________________________________________.
7. Nobody can solve the mystery.
__________________________________________________.
IV> Choose the best answer
1. You should ____________ attention to what your teacher is saying.
A. take B. give C. have D. pay
2. Chung Cake (square sticky rice cake), pho (rice noodles), Nem (spring rolls) are the _______food in
Vietnam.
A. Tradition B. traditional C. traditionally D. traditionalism
3. Table __________ are always paid attention to by the British.
A. Meaning B. meals C. manners D. decoration
4. Amish’s wedding __________ in the spring.
A. Take after B. take over C. take place D. take along
5. The newly-wedding couple plan to spend their ____________ in India.
A. Honeymoon B. ceremony C. bride D. groom
6. Some people think that married women ________ pursue a career.
A. shouldn’t B. might not C. mustn’t D. might not
7. We _________ stop when traffic lights are red.
A. must B. should C. might D. can
8. Remember to bring your raincoat. It ____________ rain.
A. might B. should C. can D. must
9. You ________ pick those flowers. Don’t you see the sign?
A. mustn’t B. don’t need to C. can’t D. needn’t
10 .It’s late. I think we............. better go now.
A. had B. have C. should D. would
11. We................................ take a bus to the school. It’s too far to walk.
A. have to B. must C. may D. ought
12. You................... be very tall to play football.
A. don’t have to B. mustn’t C. may not D. can’t
13. We ………… get there on time. The boss is away today.
A. mustn’t B. don’t have to C. can’t D. couldn’t
14. I _______ find my own way there. You _______ wait for me.
a. should / can't b. have to / must c. can / needn't d. might / mustn't
15. Jane gave me a letter to post. I _________ forget to post it.
A. mustn’t B. needn’t C. shouldn’t D. won’t
16. Jane gave me a letter to post. I _________ remember to post it.
A. must B. mustn’t C. can D. might
17. The picnic ________ because Peter has just had a traffic accident.
a. will cancel b. will be cancelling c. will be cancelled d. will have cancelled
18. Things ________ clear to them so that they can do the work in the way that you have told them.
a. are making b. ought to be made c. have made d. needn't be made
19. Cigarettes ________ at a bakery.
a. most buy b. cannot buy c. cannot be bought d. should not buy
29. All traffic laws ________.
a. is observed b. must be observed c. must have observed d. had better observe
21. This letter ________, not handwritten.
a. should be typing b. should be typed c. needn't type d. needn't be typed
22. Fruits ________ in a freezer.
a. should not put b. should not be put c. must put d. must be putting
23. The last decision ________.
a. will be made by the manager b. needn't be finished / will be having
c. that will be made by the manager d. must be finished / can have
24. The package ________ carefully before it ________.
a. must be wrapped / is posted b. needs wrapping / will be posted
c. should wrap / is going to be posted d. will be wrapping / needs posting
25. Shall we start working __________ our project “Equal opportunity in education?”
A. on B. out C. at D. in
I. Circle A, B, C or D to choose the words with different stress
1. A. pursue B. enrol C,.equal D. repeat
2. A. lonely B. alone C. major D. famous
3. A. income B. workforce C. nature Dmature
4. A. knowledge B. challenge C .enjoy D. labor
5. A. pretty B. freedom C. happen D. begin
II. Give the correct form of the verb in brackets in the passive voice
1. A new monitor will be selected (will/select) by the members of the class next semester.
2. Information (can/find) can be found due to the aid of the Internet.
3. If you want your car to be in good condition, it (must/service) must be serviced frequently.
4. Students (not/should/give) should not be given everything about the subjects by their lecturers. They need to be creative and
discover new knowledge.
5. This house (must/sell) must be sold within 2 months.
6. When people have experienced something terrible, funny things (can/do).can be done
7. A valid work permit (must/hold) must be held by all employees.
8. Advice from the experts (should/take) should be taken by the government before making the new law.
9. Cultural differences (ought to/consider) ought to be considered by companies when engaging in business with overseas
organizations.
10. Some changes to our lives (must/ make) must be made if we want to reduce pollution
III. Change the following sentences into passive voice.
1. You should finish the work before you leave.
=> The work should be finished by you before you leave.
2. You can serve this wine with chicken or fish.
-> This wine can be served with chicken or fish
3.
We will elect a new government next year.
-> A new government will be elected by us next year
4. They might give him an award.
=> He might be given an award
=> An award might be given to him
5. You must give students enough time to finish.
=> Students must be give enough time to finish.
6. You should keep flowers in a warm sunny place.
-> Flowers should be kept in a warm sunny place ( by you).
7. Nobody can solve the mystery.
=> The mystery can't be solved.
IV> Choose the best answer
1. You should ____________ attention to what your teacher is saying.
A. take B. give C. have D. pay
2. Chung Cake (square sticky rice cake), pho (rice noodles), Nem (spring rolls) are the _______food in
Vietnam.
A. Tradition B. traditional C. traditionally D. traditionalism
3. Table __________ are always paid attention to by the British.
A. Meaning B. meals C. manners D. decoration
4. Amish’s wedding __________ in the spring.
A. Take after B. take over C. take place D. take along
5. The newly-wedding couple plan to spend their ____________ in India.
A. Honeymoon B. ceremony C. bride D. groom
6. Some people think that married women ________ pursue a career.
A. shouldn’t B. might not C. mustn’t D. might not
7. We _________ stop when traffic lights are red.
A. must B. should C. might D. can
8. Remember to bring your raincoat. It ____________ rain.
A. might B. should C. can D. must
9. You ________ pick those flowers. Don’t you see the sign?
A. mustn’t B. don’t need to C. can’t D. needn’t
10 .It’s late. I think we............. better go now.
A. had B. have C. should D. would
11. We................................ take a bus to the school. It’s too far to walk.
A. have to B. must C. may D. ought
12. You................... be very tall to play football.
A. don’t have to B. mustn’t C. may not D. can’t
13. We ………… get there on time. The boss is away today.
A. mustn’t B. don’t have to C. can’t D. couldn’t
14. I _______ find my own way there. You _______ wait for me.
a. should / can't b. have to / must c. can / needn't d. might / mustn't
15. Jane gave me a letter to post. I _________ forget to post it.
A. mustn’t B. needn’t C. shouldn’t D. won’t
16. Jane gave me a letter to post. I _________ remember to post it.
A. must B. mustn’t C. can D. might
17. The picnic ________ because Peter has just had a traffic accident.
a. will cancel b. will be cancelling c. will be cancelled d. will have cancelled
18. Things ________ clear to them so that they can do the work in the way that you have told them.
a. are making b. ought to be made c. have made d. needn't be made
19. Cigarettes ________ at a bakery.
a. most buy b. cannot buy c. cannot be bought d. should not buy
29. All traffic laws ________.
a. is observed b. must be observed c. must have observed d. had better observe
21. This letter ________, not handwritten.
a. should be typing b. should be typed c. needn't type d. needn't be typed
22. Fruits ________ in a freezer.
a. should not put b. should not be put c. must put d. must be putting
23. The last decision ________.
a. will be made by the manager b. needn't be finished / will be having
c. that will be made by the manager d. must be finished / can have
24. The package ________ carefully before it ________.
a. must be wrapped / is posted b. needs wrapping / will be posted
c. should wrap / is going to be posted d. will be wrapping / needs posting
25. Shall we start working __________ our project “Equal opportunity in education?”
A. on B. out C. at D. in
Mark the letter a, B, C, or D on your answer sheet to indicate the sentence that is closest meaning to each of the following questions or indicate the correct answer to each of them from 1 to 7
It is estimated that over 99 percent of all species that ever existed have become extinct. What causes extinction? When a species is no longer adapted to a changed environment, it may perish. The exact causes of a species’ death vary from situation to situation. Rapid ecological change may render an environment hostile to a species. For example, temperatures may change and a species may not be able to adapt. Food resources may be affected by environmental changes, which will then cause problems for a species requiring these resources. Other species may become better adapted to an environment, resulting in competition and, ultimately, in the death of a species.
The fossil record reveals that extinction has occurred throughout the history of Earth. Recent analyses have also revealed that on some occasions many species become extinct at the same time- a mass extinction. One of the best- known examples of mass extinction occurred 65 million years ago with the demise of dinosaurs and many other forms of life. Perhaps the largest mass extinction was the one that occurred 225 million years ago, when appropriately 95 percent of all species died. Mass extinction can be caused by a relatively rapid change in the environment and can be worsened by the close interrelationship of many species. If, for example, something were to happen to destroy much of the plankton in the oceans, then the oxygen content of Earth would drop, affection even organisms not living in the ocean. Such a change would probably lead to a mass extinction.
One interesting, and controversial, finding is that extinctions during the past 250 million years have tended to be more intense every 26 million years. This periodic extinction might be due to intersection of the Earth’s orbit with a cloud of comets, but this theory is purely speculative. Some researchers have also speculated that extinction may often be random. That is, certain species may be eliminated and others may survive for no particular reason. A species’ survival may have nothing to do with its ability to adapt. If so, some of evolutionary history may reflect a sequence of essentially random events.
Why is “plankton” mentioned in the second paragraph?
A. To demonstrate the interdependence of different species
B. To illustrate a comparison between organisms that live on the land and those that live in the ocean
C. To emphasize the importance of food resources in preventing mass extinction
D. To point out that certain species could never become extinct
Đáp án A
Tại sao sinh vật phù du được đề cập tới ở đoạn 2?
A. Để chứng minh sự phụ thuộc giữa các loài khác nhau.
B. Để minh họa cho sự so sánh giữa các sinh vật sống trên mặt đất và những sinh vật sống trong đại dương.
C. Để nhấn mạnh tầm quan trọng của nguồn thức ăn trong việc ngăn chặn sự tuyệt chủng hàng loạt.
D. Để chỉ ra rằng một số loài nhất định sẽ không bao giờ bị tuyệt chủng.
Dẫn chứng ở câu thứ 5+6 ở đoạn 2: “ Mass extinction can be caused by a relatively rapid change in the environment and can be worsened by the close interrelationship of many species. If, for example, something were to happen to destroy much of the plankton in the oceans, then the oxygen content of Earth would drop, affection even organisms not living in the ocean” – ( Sự tuyệt chủng hàng loạt bị gây ra bởi sự biến đổi môi trường nhanh chóng và có thể tồi tệ hơn là do mối tương quan mật thiết giữa các loài. Ví dụ như có điều gì đó xảy ra làm hủy diệt số lượng lớn các loài sinh vật phù dù trong đại dương, thì lượng ô-xi trên trái đất cũng từ đó mà giảm theo làm ảnh hưởng không chỉ tới các loài sinh vật đại dương).
Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.
It is estimated that over 99 percent of all species that ever existed have become extinct. What causes extinction? When a species is no longer adapted to a changed environment, it may perish. The exact causes of a species’ death vary from situation to situation. Rapid ecological change may render an environment hostile to a species. For example, temperatures may change and a species may not be able to adapt. Food Resources may be affected by environmental changes, which will then cause problems for a species requiring these resources. Other species may become better adapted to an environment, resulting in competition and, ultimately, in the death of a species.
The fossil record reveals that extinction has occurred throughout the history of Earth. Recent analyses have also revealed that on some occasions many species became extinct at the same time – a mass extinction. One of the best-known examples of mass extinction occurred 65 million years ago with the demise of dinosaurs and many other forms of life. Perhaps the largest mass extinction was the one that occurred 225 million years ago. When approximately 95 percent of all species died, mass extinctions can be caused by a relatively rapid change in the environment and can be worsened by the close interrelationship of many species. If, for example, something were to happen to destroy much of the plankton in the oceans, then the oxygen content of Earth would drop, affection even organisms not living in the oceans. Such a change would probably lead to a mass extinction.
One interesting, and controversial, finding is that extinctions during the past 250 million years have tended to be more intense every 26 million years. This periodic extinction might be due to intersection of the Earth’s orbit with a cloud of comets, but this theory is purely speculative. Some researchers have also speculated that extinction may often be random. That is, certain species may be eliminated and others may survive for no particular reason. A species’ survival may have nothing to do with its ability or inability to adapt. If so, some of evolutionary history may reflect a sequence of essentially random events
Which of the following can be inferred from the theory of periodic extinction mentioned in paragraph 3?
A. Many scientists could be expected to disagree with it
B. Evidence to support the theory has recently been found
C. The theory is no longer seriously considered
D. Most scientists believe the theory to be accurate
Đáp án A
Từ học thuyết tuyệt chủng chu kì đuộc đề cập ở đoạn 3, có thể suy ra điều gì?
A. rất nhiều nhà khoa học có thể phản đối nó
B. hầu hết các nhà khoa học tin học thuyết này là đúng
C. học thuyết này không còn được xem xét một cách nghiêm túc nữa
D. bằng chứng để ủng hộ học thuyết này đã được tìm ra
Giải thích: Thông tin nằm ở “This periodic extinction might be due to intersection of the Earth’s orbit with a cloud of comets, but this theory is purely speculative”. Vì nó hoàn toàn là suy đoán nên ta có thể suy đoán rằng nó bị nhiều nhà khoa học khác phản đối
Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 28 to 34.
It is estimated that over 99 percent of all species that ever existed have become extinct. What causes extinction? When a species is no longer adapted to a changed environment, it may perish. The exact causes of a species' death vary from situation to situation. Rapid ecological change may render an environment hostile to a species. For example, temperatures may change and a species may not be able to adapt. Food Resources may be affected by environmental changes, which will then cause problems for a species requiring these resources. Other species may become better adapted to an environment, resulting in competition and, ultimately, in the death of a species.
The fossil record reveals that extinction has occurred throughout the history of Earth. Recent analyses have also revealed that on some occasions many species became extinct at the same time - a mass extinction. One of the best-known examples of mass extinction occurred 65 million years ago with the demise of dinosaurs and many other forms of life. Perhaps the largest mass extinction was the one that occurred 225 million years ago. When approximately 95 percent of all species died, mass extinctions can be caused by a relatively rapid change in the environment and can be worsened by the close interrelationship of many species. If, for example, something were to happen to destroy much of the plankton in the oceans, then the oxygen content of Earth would drop, affection even organisms not living in the oceans. Such a change would probably lead to a mass extinction.
One interesting, and controversial, finding is that extinctions during the past 250 million years have tended to be more intense every 26 million years. This periodic extinction might be due to intersection of the Earth’s orbit with a cloud of comets, but this theory is purely speculative. Some researchers have also speculated that extinction may often be random. That is, certain species may be eliminated and others may survive for no particular reason. A species’ survival may have nothing to do with its ability or inability to adapt. If so, some of evolutionary history may reflect a sequence of essentially random events.
Which of the following can be inferred from the theory of periodic extinction mentioned in paragraph 3?
A. Many scientists could be expected to disagree with it
B. Evidence to support the theory has recently been found.
C. The theory is no longer seriously considered.
D. Most scientists believe the theory to be accurate.
Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 43 to 50.
It is estimated that over 99 percent of all species that ever existed have become extinct. What causes extinction? When a species is no longer adapted to a changed environment, it may perish. The exact causes of a species' death vary from situation to situation. Rapid ecological change may render an environment hostile to a species. For example, temperatures may change and a species may not be adapted. Food resources may be affected by environmental changes, which will then cause problems for a species requiring these resources. Other species may become better adapted to an environment, resulting in competition and, ultimately, in the death of a species.
The fossil record reveals that extinction has occurred throughout the history of Earth. Recent analyses have also revealed that on some occasions many species became extinct at the same time - a mass extinction. One of the best-known examples of mass extinction occurred 65 million years ago with the demise of dinosaurs and many other forms of life. Perhaps the largest mass extinction was the one that occurred 225 million years ago, when approximately 95 percent of all species died. Mass extinctions can be caused by a relatively rapid change in the environment and can be worsened by the close interrelationship of many species. If, for example, something were to happen to destroy much of the plankton in the oceans, then the oxygen content of Earth would drop, even affect organisms not living in the oceans. Such a change would probably lead to a mass extinction.
One interesting, and controversial, finding is that extinctions during the past 250 million years have tended to be more intense every 26 million years. The periodic extinction might be due to intersection of the earth's orbit with a cloud of comets, but this theory is purely speculative. Some researchers have also speculated that extinction may often be random. That is, certain species may be eliminated and others may survive for no particular reason. A species' survival may have nothing to do with its ability or inability to adapt. If so, some of revolutionary history may reflect a sequence of essentially random events.
Question 49: Which of the following can be inferred from the theory of periodic extinction mentioned in paragraph 3?
A. many scientists could be expected to disagree with it.
B. most scientists believe the theory to be accurate.
C. the theory is no longer seriously considered.
D. evidence to support the theory has recently been found.
Đáp án A
Dịch nghĩa: Từ học thuyết tuyệt chủng chu kì được đề cập ở đoạn 3 có thể suy ra điều gì?
A. rất nhiều nhà khoa học có thể phản đối nó.
B. hầu hết các nhà khoa học tin học thuyết này là đúng.
C. học thuyết này không còn được xem xét một cách nghiêm túc nữa.
D. bằng chứng để ủng hộ học thuyết này đã được tìm ra.
Giải thích: Thông tin nằm ở “The periodic extinction might be due to intersection of the earth’s orbit with a cloud of comets, but this theory is purely speculative”. Vì nó hoàn toàn là suy đoán nên ta có thể suy đoán rằng nó bị nhiều nhà khoa học khác phản đối.