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问题 多选题

若A→B→C为某生态系统中的唯一食物链。该生态系统接受的年太阳辐射量为200000百万千焦，但其中绝大部分能量未能被生产者固定。该食物链中各种群对能量的同化、利用、传递与散失等各部分的数量关系如表(单位：百万千焦)。则在该年度内

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A．B摄食后未同化的能量值为4.5百万千焦

B．B的净生产量为9百万千焦

C．该生态系统的能量净增加值为148百万千焦

D．从B→C的传递效率为15%

答案

ABD

阅读理解

I am a mother of two children. Like many other parents, I worry(担心) that my children watch too much TV. Why? First, there are lots of bad programmes (节目) on TV. They may learn from them. Second, watching too much TV is bad for their eyes. Many students wear glasses because they watch TV for long hours. Third, watching too much TV makes children think little(少). I think it is very important for children to read some books. Reading books makes children think more. When I tell this to my children, they just don't listen to me. So I decide to sell the television set. Maybe it is a good idea.

小题1:Where are there a lot of bad programmes that the woman worries?

A．In films.

B．On the Internet.

C．On TV.

D．On books.小题2:Why do many students wear glasses according to the passage(文章)?

A．Because they study too hard.

B．Because they read many books.

C．Because they watch too much TV.

D．Because they have a pair of glasses.小题3:What is the best title of the passage?

A．An interesting story.

B．A mother's worry

C．Bad programmes on TV

D．Don't read books.
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单项选择题

假定每一车次具有唯一的始发站和终点站。如果实体“列车时刻表”属性为车次、始发站、发车时间、终点站、到达时间，该实体的主键是 （42） ；如果实体“列车运行表”属性为车次、日期、发车时间、到达时间，该实体的主键是 （43） 。通常情况下，上述“列车时刻表”和“列车运行表”两实体型间 （44） 联系。

（42）处填（）。

A．车次

B．始发站

C．发车时间

D．车次，始发站
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