Passage Two
　　"The world's environment is surprisingly healthy. Discuss." If that 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. 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. The reasons why they don't, and why the environment has not been mined, 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. 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. Prices fluctuate, in response to harvests, natural disasters and political instability; 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. 　　
　　It is where prices and markets do not operate properly that this benign ( 良性的 ) trend begins 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: fish is the best example of this.
　　
　　26. According to the author, most students________.
　　A) believe the world's environment is in an undesirable condition
　　B) agree that the environment of the world is not as bad as it is thought to be
　　C) get high marks for their good knowledge of the world's environment
　　D) appear somewhat unconcerned about the state of the world's environment
　　
　　27. The huge increase in world production and population ________.
　　A) has made the world a worse place to live in
　　B) has had a positive influence on the environment
　　C) has not significantly affected the environment
　　D) has made the world a dangerous place to live in
　　
　　28. One of the reasons why the long-term trend of prices has been downwards is that________.
　　A) technological innovation can promote social stability
　　B) political instability will cause consumption to drop
　　C) new farming and crop technology can lead to overproduction
　　D) new sources are always becoming available
　　
　　29. Fish resources are diminishing because________.
　　A) no new substitutes can be found in large quantities
　　B) they are not owned by any particular entity
　　C) improper methods of fishing have mined the fishing grounds
　　D) water pollution is extremely serious
　　
　　30. The primary solution to environmental problems is________.
　　A) to allow market forces to operate properly
　　B) to curb consumption of natural resources
　　C) to limit the growth of the world population
　　D) to avoid fluctuations in prices