The sea has always interested man. From it he can get food, minerals, and treasure. For th

The sea has always interested man. From it he can get food, minerals, and treasure. For thousands of years, he could sail on it. But he could not go far beneath its surface.
Man wants to explore deep into the sea. However, he is not a fish. He must breathe air, so he can't stay under the water's surface for any length of time. To explore deep water, man faces even more dangers and problems.
A diver who wants to stay under water for more than a few minutes must breathe air or a special mixture of gases. He can wear a diving suit and have air pumped to him from above. He can carry a tank of air on his back and breathe through a nose and a mouthpiece. Water weighs 800 times as much as air. Tons of water pushes against a diver deep in the sea. His body is under great pressure.
When a diver is under great pressure, his blood takes in some of the gases he breathes. As he rises to surface, the water pressure becomes less. If the diver rises too quickly, the gases in his blood form bubbles. The diver is then suffering from the bends. The bends can cause a diver to double up in pain. They can even kill him.
【小题1】On the whole, this passage is about .A．special mixtures of gases in deep seaB．the problems man faces in deep sea divingC．air pressure under the surface of sea waterD．a kind of illness that man suffers in the sea【小题2】The passage does not say so, but it makes you think that .A．deep divers should be in good healthB．divers explore the deep sea only for treasureC．diving under the water too quickly causes a kind of illnessD．there is a special mixture of gases under the sea【小题3】From the passage we can see that .A．the sea began to interest man a few years agoB．man is not at home deep in the seaC．all divers will get the bends sooner or laterD．the air in the sea water will kill a diver if he is not carefulB

(答案→)B 解析：文章介绍了人类从很早就探索海洋，从中获取吃的，矿物质，财富等等，但是很长时间以来，他们只可以航海，但是没办法去海洋的下面去，潜水员要去水面以下，就必须带氧气瓶，并且水的压力是很大的，如果下去以后在回来时速度太快，就会有身体上的不适等。【小题1】 B大意理解题。文章的第二自然段人不能在水面以下呆的时间太长，如果去探索深海，会面临更大的危险。第二自然段讲了潜水员去水下的时候要带氧气瓶，水的重量是空气重量的800倍，因此要承担很大的压力。第三自然段是潜水员去水深处时，他的血液会吸收他呼吸的气体，急速反回时，会有更大的危险。故答案应为B。【小题2】A细节理解题。文章的第三自然段讲述了潜水员要承认很大的压力，血液会吸收他呼吸的气体，如果返回太快，血液里的气体会形成气泡，就会患上减压病，会承受痛苦，甚至有生命危险，由此可知，运动员身体必须健康。故答案应为Ａ．【小题3】B细节判断题。Ａ人类在许多年前就开始探索大海，而第一自然段人类探索大海数千年了，故Ａ是错误的；all divers will get the bends sooner or later所有的潜水员都迟早会患减压病的，这在文章当中是无法反映出的；文章的最后一自然段最后一句话是说减压病可能会使一个人丧生，不是海水中的空气，是错误的，故Ｂ是正解的，人类在深海是不可能安家的。【考点】考查科普环保类文章的阅读理解。

我学会了