2009年12月大学英语四级考试模拟试题(十)

　　M: I'm sure you are right. The diesel bus isn't exactly pollution free.

　　W: True. They'll be running a lot cleaner soon. We were just talking about that in my environmental engineering class.

　　M: What could the city do? Install pollution filters in all their buses?

　　W: They could, but those filters make the engines work harder and really cut down on the fuel efficiency. Instead they found a way to make their engines more efficient.

　　M: How?

　　W: Well, there is a material that's a really good insulator. And a thin coat of it gets sprayed on the certain part of the engine.

　　M: An insulator?

　　W:Y eah. What it does is reflect back the heat of burning fuel. So the fuel will burn much hotter and burn up more completely.

　　M: So a lot less unburned fuel comes out to pollute the air.

　　W: And the bus will need less fuel. So with the saving on fuel cost, they say this will all pay for itself in just six months.

　　M: Sounds like people should all go out and get some this stuff to spray their car engines.

　　W: Well, it's not really that easy. You see, normally, the materials are fine powder. To melt it so you can spray a coat of it on the engine parts, you first have to heat it over 10000 degrees and then, well, you get the idea. It's not something you or I will be able to do ourselves.

　　Questions 23 to 25 are based on the conversation you have just heard.

　　23. What is the conversation mainly about?

　　【解析】[C]女士说为了环保应该多乘坐公共交通设备，因此之后的话题便围绕如何节能保护环境的问题展开。这段对话主要讨论的是公共汽车的节能问题，讨论了如何让公共汽车燃料更有效的利用，因此[C]符合题意。

　　24. Why did the woman decide to ride the city bus?

　　【解析】[B]对话开头部分就交代了此题答案，那位女士说她不开自己的车而该乘公车是为了降低环境污染。从她提到的So I decided the air will be a lot cleaner if we all use public transportation when we could 即可得知。

　　25. What is the new material?

　　【解析】[D] 这种新的材料是在引擎部位喷洒的一种绝缘材料。从女士的话中there is a material that's a really good insulator. And a thin coat of it gets sprayed on the certain part of the engine即可得出。这种材料的用途是将燃料燃烧的热量反射回去，从而达到提高效率的结果。