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.
In paragraph 3, the author makes which of the following statements about a species' survival?
A. it may depend on chance events.
B. it does not vary greatly from species to species
C. it reflects the interrelationship of many species.
D. it is associated with astronomical conditions.
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Đáp án A
Dịch nghĩa: Ở đoạn 3, tác giả nói gì về sự tồn tại của một loài?
A. Nó có thể phụ thuộc vào những việc xảy ra tình cờ.
B. Nó không khác nhau nhiều giữa các loài.
C. Nó phản ánh mối liên hệ giữa các loài.
D. Nó liên quan đến điều kiện thiên văn học.
Bài dịch
Người ta ước tính rằng hơn 99 phần trăm tất cả các loài từng tồn tại đã bị tuyệt chủng. Điều gì gây ra sự tuyệt chủng? Khi một loài không còn thích nghi với môi trường đã thay đổi, nó có thể biến mất. Các nguyên nhân chính dẫn đến một loài chết đi khác nhau đối với các trường hợp khác nhau. Sự thay đổi hệ sinh thái quá nhanh có thể khiến môi trường sống trở nên khó khăn với các loài đó. Ví dụ, nhiệt độ có thể thay đổi mà một loài không thể thích nghi. Nguồn thức ăn có thể bị ảnh hưởng bởi những thay đổi của môi trường, sau đó sẽ tiếp tục gây ra những vấn đề khác cho loài mà cần sử dụng nguồn thức ăn này. Các loài khác có thể thích nghi tốt hơn với môi trường, dẫn đến sự cạnh tranh và cuối cùng, là cái chết của một loài nào đó.
Các mẫu hóa thạch cho thấy rằng sự tuyệt chủng đã xảy ra trong suốt lịch sử của trái đất. Phân tích gần đây cũng tiết lộ rằng trong một số trường hợp nhiều loài đã tuyệt chủng cùng lúc - tuyệt chủng hàng loạt. Một trong những ví dụ nổi bật nhất của tuyệt chủng hàng loạt xảy ra vào 65 triệu năm trước đây với sự sụp đổ của khủng long và nhiều sinh vật sống khác. Có lẽ lần tuyệt chủng hàng loạt lớn nhất xảy ra vào 225 triệu năm trước đây, khi khoảng 95 phần trăm số loài đã chết. Tuyệt chủng hàng loạt có thể bị gây ra bởi sự thay đổi tương đối nhanh chóng của môi trường và có thể trở nên tồi tệ hơn bởi các mối liên hệ mật thiết giữa các loài. Ví dụ, nếu một điều gì đó đã xảy ra và tiêu diệt nhiều sinh vật phù du trong các đại dương, sau đó hàm lượng oxy của trái đất sẽ giảm, thậm chí ảnh hưởng đến các sinh vật không sống trong đại dương. Một sự thay đổi như vậy có thế sẽ dẫn đến sự tuyệt chủng hàng loạt.
Một khám phá thú vị, và cũng gây nhiều tranh cãi, đó là sự tuyệt chủng trong suốt 250 triệu năm qua đã có xu hướng tăng mạnh mẽ hơn sau mỗi 26 triệu năm. Sự tuyệt chủng có chu kỳ này có thể là do giao điểm của quỹ đạo trái đất với một đám mây sao chổi, nhưng thuyết này hoàn toàn chỉ là suy đoán. Một số nhà nghiên cứu cũng đã cho rằng sự tuyệt chủng thường là ngẫu nhiên. Nghĩa là một số loài bị loại bỏ và những loài khác có thể tiếp tục tồn tại mà không có lý do cụ thể nào. Sự tồn tại của một loài có thể không liên quan gì đến khả năng thích nghi hay không thích nghi của chúng. Nếu vậy, một vài sự tiến hóa lịch sử có thể phản ánh một chuỗi các sự kiện ngẫu nhiên quan trọng.
Mark the letter A, B, C or D to indicate the word that differs from the other three in the position of the primary stress in each of the following questions.
Mark the letter A, B, C or D to indicate the word or phrase that is OPPOSITE in meaning to the underlined part in each of the following questions.
In 1989, a ban was given on all international trade in ivory.
Mark the letter A, B, C or D to indicate the sentence that best combines each pair of sentences in the following questions.
The Prime Minister set up a committee of financial experts. They ere to help him discuss and formulate new policies.
Read the following passage and mark the letter A, B, C or D to indicate the correct word or phrase that
best fits each of the numbered blanks from 31 to 35.
Early writing and Alphabets
When people first began to write, they did not use an alphabet. Instead, they drew small pictures to (31) _______ the objects they were writing about. This was very slow because there was a different picture for every word.
The Ancient Egyptians had a (32) _______of picture writing that was called hieroglyphics. The meaning of this writing was forgotten for a very long time but in 1799 some scientists (33) _______ a stone near Alexandria, in Egypt. The stone had been there for over a thousand years. It had both Greek and hieroglyphics on it and researchers were finally able to understand what the hieroglyphics meant.
An alphabet is quite different from picture writing. It (34) _______of letters or symbols that represent a sound and each sound is just part of one word. The Phoenicians, who lived about
3,000 years ago, developed the modern alphabets. It was later improved by the Roman's and this alphabet is now used (35) _______ throughout the world.
Điền vào ô 34.
Mark the letter A, B, C or D to indicate the word that differs from the other three in the position of the primary stress in each of the following questions.
Mark the letter A, B, C or D to indicate the sentence that is closest in meaning to each of the following questions.
Ironically, the new model is nowhere near as reliable as the old one.
Read the following passage and mark the letter A, B, C or D to indicate the correct word or phrase that
best fits each of the numbered blanks from 31 to 35.
Early writing and Alphabets
When people first began to write, they did not use an alphabet. Instead, they drew small pictures to (31) _______ the objects they were writing about. This was very slow because there was a different picture for every word.
The Ancient Egyptians had a (32) _______of picture writing that was called hieroglyphics. The meaning of this writing was forgotten for a very long time but in 1799 some scientists (33) _______ a stone near Alexandria, in Egypt. The stone had been there for over a thousand years. It had both Greek and hieroglyphics on it and researchers were finally able to understand what the hieroglyphics meant.
An alphabet is quite different from picture writing. It (34) _______of letters or symbols that represent a sound and each sound is just part of one word. The Phoenicians, who lived about
3,000 years ago, developed the modern alphabets. It was later improved by the Roman's and this alphabet is now used (35) _______ throughout the world.
Điền vào ô 32.
Mark the letter A, B, C or D to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions.
Read the following passage and mark the letter A, B, C or D to indicate the correct word or phrase that
best fits each of the numbered blanks from 31 to 35.
Early writing and Alphabets
When people first began to write, they did not use an alphabet. Instead, they drew small pictures to (31) _______ the objects they were writing about. This was very slow because there was a different picture for every word.
The Ancient Egyptians had a (32) _______of picture writing that was called hieroglyphics. The meaning of this writing was forgotten for a very long time but in 1799 some scientists (33) _______ a stone near Alexandria, in Egypt. The stone had been there for over a thousand years. It had both Greek and hieroglyphics on it and researchers were finally able to understand what the hieroglyphics meant.
An alphabet is quite different from picture writing. It (34) _______of letters or symbols that represent a sound and each sound is just part of one word. The Phoenicians, who lived about
3,000 years ago, developed the modern alphabets. It was later improved by the Roman's and this alphabet is now used (35) _______ throughout the world.
Điền vào ô 31.
Mark the letter A, B, C or D to indicate the sentence that is closest in meaning to each of the following questions.
"Lily has a lot on her mind", Mrs. Baker said.
Mark the letter A, B, C or D to indicate the most suitable response to complete each of the following exchanges.
Ken and Tom are high-school students. They meet each other at a gallery but Ken is in a hurry.
Ken: “I've got to go, Tom. So long”
Tom: “So long, Ken. And _______.”
Mark the letter A, B, C or D to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions.
Mark the letter A, B, C or D to indicate the sentence that is closest in meaning to each of the following questions.
Did he mean to hurt her or did that happen accidentally?
Mark the letter A, B, C or D to indicate the underlined part that needs correction in each of the following questions.
(A) The populace was (B) so terrified of the tornado that (C) however town she visited she found (D) villages deserted of inhabitants and livestock.
Mark the letter A, B, C or D to indicate the most suitable response to complete each of the following exchanges.
- “How about giving me a hand?” – “____________.”
