Question

　　   As a result of pollution, Lake Erie, on the borders of the U. S. A. and Canada, is now without any living things.

　　   Pollution in water is not simply a matter of "poisons" killing large number of fish overnight. Very often the effects of pollution are not noticed for many months of years because the first organisms（生物体）to be affected are either plants or plankton（浮游生物）.But these organisms are the food of fish and birds and other creatures. When this food disappears, the fish and birds die too. In this way a whole food chain can be wiped out, and it is not until dead fish and water birds are seen at the river's edge or on the sea shore that people realize that is happening.

　　   Where do the substances（物质）which pollute the water come from? There are two main sources-sewage（污水）and industrial waste. As more detergent（洗涤剂）is used in the home, more of it is finally put into our rivers, lakes and seas. Detergents harm water birds, dissolving（分解）the natural substances which keep their feather waterproof. Sewage itself, if it is not properly treated, makes the water dirty and prevents all forms of life in rivers and lakes from receiving the oxygen they need. Industrial waste is even more harmful since there are many highly poisonous things in it, such as copper and lead（铅）.

　　   So, if we want to stop this pollution, the answer is simple: Sewage and industrial waste must be made clean before flowing into the water. It may already be too late to save some rivers and lakes, but others can still be saved if the correct action is taken at once.　　

1. What is the meaning of the word "waterproof" in the third paragraph? It means "　　　　　　   ".

A. full of water　　　　　　 B. not allowing water to go through

C. covered with water　　    D. cleaned by water

2. Which of the following is harmless according to the passage?

A. Industrial waste.　　　　　　　　　　 B. Chemicals.

C. Water for cleaning.　　　　   D. Natural substances.

3. The way to stop water pollution is 　　　　　　    .

A. to realize the serious situation clearly

B. to put oxygen into the river

C. to make the waste materials harmless

D. to make special room in the sea for our rubbish

 

Answer 1

答案：B;D;C
解析：

1.       waterproof防水的，不透水的。 2.       可采用排除法。Natural substances自然物质。 3.       参见最后一段。

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