Now you'll hear the two long conversations.
Conversation One
M: Hi, Diana. I'm surprised to see you on the city bus. Your car in the shop?
W: No. [19]I've just been thinking a lot about the environment lately. So I decided the air will be a lot cleaner if we all use public transport when we could.
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. [20]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 new insulator. And you spray a thick coat of it on the engine.
M: An insulator?
W: Yeah. [21]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.

Questions 19 to 22 are based on the conversation you have just heard.
19. Why does Diana take a bus that day?
正確答案：A
解析：男士問Diana為什么乘坐公共汽車，是不是她的汽車在維修。女士回答說不是，她乘坐公共汽車是因為最近她在考慮環境問題。大家都使用公共交通的話，空氣會干凈一些?？梢娝P注環境，故A正確。B未提及，C、D內容與對話不符。
20. What is true about Diana?
正確答案：C
解析：女士說到：“在環境工程課上我們剛剛談到過這一點?！笨梢娝蘖艘婚T環境工程課，故C正確。四個選項都以Diana為主語，本題定然問她的情況。要根據選項關鍵詞聽對話，把涉及關鍵詞的信息與選項對照，判斷選項正誤。
21. What justifies the installation of a new insulator in the buses according to Diana?
正確答案：A
解析：對于安裝新的絕熱器，女士說：“它的作用在于它可以把燃料燃燒的熱量反射回來，這樣燃料燃燒時的溫度就會更高，燃燒也就更徹底?！笨梢娊^熱器可以提高燃燒率，A正確。鑒于我們并不知道it指什么，聽錄音時，必須對有關事物予以重視。對話中，男士重復反問了一個詞“An insulator?”表明它是對話中討論的一個重點，問題it可能與它有關。緊接著女士的回答又用了“What it does is...”的強調結構，并用“So...”說明結果，相關內容即構成本題答案。
22. What is the major concern of the woman?
正確答案：D
解析：對話中女士有車不開，寧愿擠公交車；上環境工程課；對節能環保絕熱器感興趣，均表明她關注環境，有濃厚的環保意識。因此，D正確。實際上本題是問對話主題，選項D概括性最強，是答案。其余選項均是細節，或與對話無關。