题干

在研究大气现象时,把温度、压强相同的一部分空气作为研究对象(不考虑分子势能),叫做“气团”。气团的直径可达到几千米。由于气团很大,可以认为其边缘部分与外界的热交换对整个气团的内能没有明显的影响。晴朗的白天,地面附近气团的温度升高,密度减小,因而上升。上升过程中压强减小,体积膨胀。在气团上升过程中,下列判断正确的是(  )

A:温度一定不变

B:温度一定升高

C:温度一定降低

D:温度可能升高、可能不变,也可能降低

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答案(点此获取答案解析)

C

同类题3

阅读下面短文,掌握其大意,然后从1~20各题所给的四个选项(A、B、C和D)中,选出最佳选项。

    Some people are afraid of starting a casual(随意的) conversation with a stranger because of a fear of not having anything interesting to say. Fear of refused is also a1for keeping silent. Small talk in a conversation can 2 as a way of warming up and getting to3each other. Most people, no matter 4 successful they are at work, will find the process of 5 small talk uncomfortable, even meaningless.6 , you will have a pretty small world 7 you refuse to let others in. Starting off with a casual comment or question will make others 8, and even just greeting them with a simple “hello” will often be enough.

    Once you have made the first 9 , there is no turning back. You need to keep things 10  before you can politely say goodbye. Think about what you would like to 11 with a new friend and that is what you can ask the other person about. Work, family, hobbies or interests are some12_points of discussion. To keep the ball rolling, you can show that you are really 13in what they are saying. Once you find common 14 of interest, things will certainly15 off from there.

    Small talk can16out to be a pleasant experience. The conversation 17 be brief and casual without turning into a long and boring discussion. Do not let yourself 18 the conversation. Stop worrying about how big of a fool you may appear to be. You may19 find out later on that you have the “20” of getting people to open up to you by engaging them in small talk.