单选题 We recently sailed with our research ship through the Red Sea to the Indian Ocean where we did research work for about a year. Our main objectives (目标) were the little-known Maldive Islands. The Maldives consist of several thousand little islands, some so small that they are hardly a mile in diameter, some as large as twenty or thirty miles across. All the islands in the Maldives have developed on coral reefs (珊瑚礁).
A coral reef is a flower garden of stone, growing like a wall or like a tower from the depths, and filled with the most confusing and most colourful varieties of life. The colours are very beautiful, especially in the shallow region down to sixty feet, where some of the red and yellow light of the sun's rays still penetrates. But most corals are greenish, brown, bluish or yellow. Coral reefs offer shelter and food to thousands of creatures. The warmer the climate, the greater the variety of species there is. In the tropics, it is easier to find, in one place, ten different species than ten specimens of the same species, and a coral reef provides ample proof of that rule. Living conditions are most favourable so that many forms are able to develop and survive in their struggle for existence. Here is wide field for the diving biologist.
The value of aqualung (水中呼吸器) diving for the biologist is that he can watch and collect on the spot. If men have not until recently ventured diving in the tropical seas, this has been mainly because of sharks. In the last twenty years I have encountered most of the really dangerous varieties of shark. There is always a certain risk, but, in general, sharks are much less dangerous than people think. You must not show fear or swim quickly away when they come into view. This attracts them, just as a cat is attracted by something on a string. Keep quiet, and, if the shark really heads towards you, then you can scare him off by swimming towards him yourself.

单选题 The colours of a coral reef are most beautiful ______ .

A. near the bottom of the sea
B. above the water level
C. within twenty meters under the water level
D. below twenty meters from the water level

【正确答案】 C

【答案解析】[解析] 参看该句“The colours are very beautiful，especially in the shallow region down to sixty feet”。

单选题 Large varieties of creatures can be found around a coral reef because ______ .

A. the coral reef exists in regions with warm climate
B. the coral reef provides favorable living conditions for them
C. the creatures are away from the danger of being eaten by sharks
D. most sea creatures feed on the colourful coral

【正确答案】 C

【答案解析】[解析] 文章第二段说明珊瑚礁可以给许多生物提供生息地，故选C。

单选题 From the author's point of view, ______ .

A. the shark is a fierce animal and dangerous to a certain extent
B. the shark looks fierce but is rarely dangerous
C. when a diving man sees a shark the best way for him to do is to swim away quickly
D. a diving man should swim toward the shark and scare it off as soon as he sees it

【正确答案】 A

【答案解析】[解析] 文中“There is always a certain risk，but，in general，sharks are much less dangerous than people think.”意思是说，鲨鱼远非人们所说的那样危险，故选A。

单选题 Which of the following statements is TRUE according to the passage?

A. The author already knew a lot about the Maldive Islands before he did research work there.
B. The climate has nothing to do with the varieties of sea creatures around the coral reef.
C. It is more difficult to find ten different kinds of animals than to find ten animals of the same kind around a tropical coral reef.
D. It was not until recently that people began to dive in the tropical seas.

【正确答案】 D

【答案解析】[解析] 参考文章最后一段。

单选题 The author of this passage is most likely to be ______ .

A. a biologist
B. an athlete
C. a reporter
D. a sailor

【正确答案】 A

【答案解析】[解析] 根据“In the last twenty years I have encountered most of the really dangerous varieties of shark.”和“We recently sailed with our research ship through the Red Sea to the Indian Ocean where we did research work for about a year．Our main objectives (目标) were the little-known Maldive Islands.”这几句话，A是正确答案。