As a result of pollution, Lake Erie, on the borders of the USA and Canada, is now without

As a result of pollution, Lake Erie, on the borders of the USA and Canada, is now without many living things.
Pollution in water is not simply a matter of “poisons” killing large numbers of fish overnight. Very often the effects of pollution are not noticed for many months or years because the first organisms (生物体) to be affected are either plants or plankton (浮游生物). These organisms are the food of fish, 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 what is happening.
Where do the substances which pollute water come from? There are two main sources, sewage(污水) and industrial waste. As more detergent (洗涤剂)is used in homes, more of it is finally put into our rivers, lakes and seas. Detergents harm water birds by breaking down the natural substances which keep their feathers waterproof. Sewage itself, if not properly treated, makes the water dirty and prevents all forms of life in rivers and the sea from receiving the oxygen they need. Industrial waste is even more harmful since there are many highly poisonous materials in it, such as copper and lead.
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 reservoirs. 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.
【小题1】Pollution in water is noticed .A．when the first organisms are affectedB．when many fish and birds dieC．when poisons are poured into waterD．As soon as the balance of nature is destroyed【小题2】Living things die in a lake or river because there is no . A．waterB．fishC．PoisonD．oxygen【小题3】The underlined word “waterproof” in the third paragraph means “ ”. A．full of waterB．not allowing water to go throughC．covered with waterD．cleaned by water【小题4】Which of the following things is /are harmful according to the passage？A．Industrial waste and chemicalsB．Water in the riverC．Coal and woodD．plasticB

(答案→)B 解析：由于污染使得美加边境的伊利湖现在已经失去了很多生物。水污染不仅仅是杀死大量的鱼类。还有很多的浮游生物和植物，然后是水鸟和其他生物。因为污水和工业废弃物没有经过适当的处理就进入河流湖泊和海洋，导致很多动植物因缺氧、中毒而亡。如果现在采取正确的措施，还可以挽救一些河流湖泊。【小题1】推理判断题。根据第一段最后一句话可知，植物先死亡，但是人们并没有注意。当鱼和鸟因吃了被污染的食物而死亡时，人们才开始注意。所以选B。【小题2】细节理解题。根据第三段 倒数第二句可知，污水使所有水里的生命不能得到他们需要的氧气而死亡。所以选D（氧气）。【小题3】词义推测题。根据第三段中waterproof所在的句子和常识的理解可知，污水含有去油的功能的洗涤剂，而鸟的羽毛自身有油脂才不能浮在水面上。所以选B（防水的）。【小题4】细节理解题。根据第三段最后一句可知，工业污水含有很多的化学物质，更有害。选A（工业废弃物和化学物质）。考点: 环保类阅读。

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