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问题 选择题

用显微镜观察腐败变质的肉汤，你会看到（　　）

A．大量的寄生虫

B．大量的苍蝇卵

C．大量的微生物

D．大量的蛋白质

答案

引起肉汤腐败变质的原因是空气中的大量的微生物落入导致的，所以用显微镜观察腐败变质的肉汤，你会看到大量的微生物．

故选：C

多项选择题

钎焊过程中，钎料能够填充接头间隙的条件就是具备( )。

A．母材熔化

B．润湿作用

C．毛细作用

D．钎料熔化

E．钎焊接头间隙大

F．钎料和母材表面有氧化物
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单项选择题

At the time friends visit us in the evening, they often tell us they are in a hurry and look at their watches. It isn’t that our friends are all very busy; it is just that we haven’t got a television. People think that we are very strange. "But what do you do in the evening", they are always asking. The answer is very simple. Both my wife and I have hobbies. We certainly don’t spend our evenings looking at the walls. My wife enjoys cooking and painting and often attends evening classes in foreign languages. This is quite useful as we often go abroad for our holidays. I collect stamps and I’m always busy with my collection. Both of us enjoy listening to the music and playing chess together.

Sometimes there are power cuts and we have no electricity in the house. This does not worry us and we just light candles and carry on with what we were doing before. Our friends, however, are lost—no television! —So they don’t know what to do. On such evenings our house is very full for they all come to us. They all have a good time. Instead of sitting in silence in front of the television, everybody talks and plays games.

At night when there is no electricity, the couple ().

A．have to look at the walls

B．can do nothing but sit in silence

C．will have many visitors

D．have to go out for candles
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