公共英语四级

单选题第53题选

参考答案:A进入在线模考
本题是顺接关系题。该句位于第五段末尾。空格之前的部分对比了动物和人类通过下载和上传的能力进行的区分,指出一般的动物只能下载,而人类除了下载,还可以上传。空格之后的内容,即第六段,则又回到了对计算机而非动物与人类比较的讨论。因此空格所填内容主要承接并且总结上文,即动物和人类之间的比较。浏览各个选项,只有A项承接这个比较。

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3根据下面资料,回答题
The world´ s environment is surprisingly healthy. Discuss. If there were an examination topic,most students would tear it apart, offering a long list of complaints from local smog (烟雾) to global climate change, from the felling (砍伐) of forests to the extinction of species. The list would largely be accurate, the concern legitimate.56) Yet the students who should be given the highest marks would actually be those who agreed with the statement. The surprise is how good
things are, not how bad.
After all, the world´ s population has more than tripled during this century, and world output has risen hugely, so you would expect the earth itself to have been affected. Indeed, if people lived, consumed and produced things in the same way as they did in 1900 (or 1950, or indeed 1980), the world by now would be a pretty disgusting place, smelly, dirty, toxic and dangerous.
But they don´ t.57) The reasons why they don´ t, and why the environment has not been ruined,have to do with prices, technological innovation, social change and government regulation in re-sponse to popular pressure. That is why today´ s environmental problems in the poor countries ought, in principle, to be solvable. Raw materials have not run out, and show no sign of doing so. Logically, one day they must: the planet is a finite place. Yet it is also very big, and man is very ingenious.58) What has happened is that every time a material seems to be running short, the price has risen and, in response, people have looked for new sources of supply, tried to find ways to use less of the material, or looked for a new substitute.
For this reason prices for energy and for minerals have fallen in real terms during the century. The same is true for food.59) Prices fluctuate, in response to harvests, natural disasters and political insta-bility; and when they rise, it takes some time before new sources of supply become available. But they always do, assisted by new farming and crop technology. The long term trend has been downwards.
60)It is where prices and markets do not operate properly that this benign ( 良性的) trend be-gins to stumble, and the genuine problems arise. Markets cannot always keep the environment healthy. If no one owns the resource concerned, no one has an interest in conserving it or fostering it: fis is the best example of this.
第56题答案