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问题 不定项选择题

下列有关苯分子中的化学键描述正确的是 [ ]

A．每个碳原子的sp2杂化轨道中的一个形成大π键

B．每个碳原子的未参与杂化的2p轨道形成大π键

C．每个碳原子的三个sp2杂化轨道与其他两个碳原子和一个氢原子形成三个σ键

D．每个碳原子的未参加杂化的2p轨道与其他原子形成σ键

答案

BC

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.

The writer tries to tell us that ______.

A．life is possible without a television
B．life is enjoyable with many friends
C．electricity is important
D．television is useful
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多项选择题

工程建设物资指的是( )。

A．建筑材料

B．建筑工具

C．建筑构配件

D．建筑设备

E．建筑机械
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