训练1：

Asteroids pose a great danger to every human on Earth. It was almost certain that an asteroid crashing into the earth made the dinosaurs extinct. There have been several near-misses in recent years. Right now, there are only a few programs designed to detect potentially dangerous asteroids, and they are almost all in the northern hemisphere. Therefore, we need a huge international program to watch the skies at all times and from both hemispheres.

训练2：

Two common forms of democratic government are the parliamentary system and the presidential system. One way in which the parliamentary system differs from the presidential system is that, under this system, power is concentrated in the elected assembly—the parliament. The executive branch is not separate from the parliament. The prime minister and the other ministers—the cabinet, in other words—are members of the assembly, and must often meet with parliament.

训练3：

Today, it is estimated that there are about 6,000 languages spoken in the world. However, many of these languages are spoken by an increasingly small number of speakers. Nearly half of them are considered endangered. One of the principal causes of this is the rise of English as a global language. English is increasingly the language of international entertainment (movies, television, and music) as well as technology, especially information technology. Almost 75% of all internet websites are in English. English is a “killer language” that is forcing out the use of smaller languages.

训练4：

Most environmentalists agree that the best way to reduce our dependence on fossil fuels is to increase the use of renewable sources of energy. According to many environmentalists, wind power is a promising method of producing energy. And it’s true that when electricity is produced by wind, there is no air pollution, no toxic or radioactive wastes from wind power. However, right now, we just can’t claim that wind energy technology causes no environmental damage. Some wind energy sites—they’re called wind farms—are very harmful to birds. The worst offender is a huge wind farm in California at a place called Altamont Pass—it’s actually the second largest wind farm in the United States. Over 5,000 birds a year are killed by the hundreds of spinning blades. These birds include golden eagles, red-tailed hawks, and other rare predators. No more wind farms should be built until we can protect birds from the dangers of wind-powered generators.

训练5：

In the last few weeks, we’ve been seeing letters to the editors in the campus newspaper from some of the faculty of the astronomy department. It seems that some of the astronomers who work nights at the Hodgkins Observatory are upset because the surrounding campus, as well as our city streets, are too well lighted. This makes it difficult, the astronomers say, for them to observe the stars and conduct their experiments.

Well, I am sorry for these scientists. However, if you ask any of the professors in the department of criminology, I’m sure they will tell you that bright lights serve as useful purpose for all of the students and for all of the residents of our city. Studies show that good lighting stops crime. It’s as simple as that. We need more nighttime light on our campus and on our streets, not less.