Question

Far from the land of Antarctica, a huge shelf of ice meets the ocean. At the underside of the shelf there lives a small fish, the Antarctic cod.

For forty years scientists have been curious about that fish. How does it live where most fish would freeze to death? It must have some secret. The Antarctic is not a comfortable place to work and research has been slow. Now it seems we have an answer.

Research was begun by cutting holes in the ice and catching the fish. Scientists studied the fish’s blood and measured its freezing point.

The fish were taken from seawater that had a temperature of -1.88℃ and many tiny pieces of ice floating in it. The blood of the fish did not begin to freeze until its temperature was lowered to -2.05℃. That small difference is enough for the fish to live at the freezing temperature of the ice-salt mixture.

The scientists’ next research job was clear: Find out what in the fish’s blood kept it from freezing. Their search led to some really strange thing made up of a protein never before seen in the blood of a fish. When it was removed, the blood froze at seawater temperature. When it was put back, the blood again had its antifreeze quality and a lowered freezing point.

Study showed that it is an unusual kind of protein. It has many small sugar molecules held in special positions within each big protein molecule. Because of its sugar content, it is called a glycoprotein. So it has come to be called the antifreeze fish glycoprotein. Or AFGP.

1.What is the text mainly about?

A. The terrible conditions in the Antarctic.

B. A special fish living in freezing waters.

C. The ice shelf around Antarctica.

D. Protection of the Antarctic cod.

2.Why can the Antarctic cod live at the freezing temperature?

A. The seawater has a temperature of -1.88℃.

B. It loves to live in the ice-salt mixture.

C. A special protein keeps it from freezing.

D. Its blood has a temperature lower than -2.05℃.

3. What does the underlined word “it” in Paragraph 5 refer to?

A. A type of ice-salt mixture.B. A newly found protein.

C. Fish blood.D. Sugar molecule.

4.What does “glyco-” in the underlined word “glycoprotein” in the last paragraph mean?

A. sugarB. ice

C. bloodD. molecule

 

Answer 1

1.B

2.C

3.B

4.A

【解析】

試題分析: 本文介紹了科學(xué)家對于南極洲一種小魚為什么能夠在如此寒冷的情況下還能生存的原因的剖析，原因在于這種魚的血液里存在的一種蛋白質(zhì)。

1.B主旨大意題。根據(jù)文章主題段第一段Far from the land of Antarctica, a huge shelf of ice meets the ocean. At the underside of the shelf there lives a small fish, the Antarctic cod.可知本文講述的是南極洲的一種小魚，故B正確。

2.C細(xì)節(jié)題。根據(jù)文章第四段The scientists’ next research job was clear: Find out what in the fish’s blood kept it from freezing. Their search led to some really strange thing made up of a protein never before seen in the blood of a fish.可知正是這種蛋白質(zhì)讓這種魚能夠再這么低溫的情況下存活。故C正確。

3.B推理題。根據(jù)Their search led to some really strange thing made up of a protein  never before seen in the blood of a fish. When it was removed, the blood froze at seawater temperature.可知當(dāng)這種物質(zhì)被拿走以后血很快就凝固了，故it就是指前面的protein，故B正確。

4.A推理題。根據(jù)Because of its sugar content, it is called a glycoprotein.可知該名詞肯定是與sugar有關(guān)，故A正確。

考點(diǎn)：科普類閱讀。