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问题 选择题

下图表示生态系统中碳循环和氮循环的一部分，A、B、C三类微生物参与其中，下列说法错误的是

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A．A类细菌是自养需氧型，B类细菌是异养厌氧型

B．C类微生物有的是自生的，有的是共生的

C．A和C的活动可增加土壤肥力

D．B的活动导致土壤氮元素丧失，没它更好

答案

答案：D

填空题

阅读短文，从方框中选择适当的动词，并用其适当形式填空。有的需要加助动词或不定式符号。

An old man died and left his son a lot of money. But the son was a foolish young man, and he quickly (1) ______________ all the money, so that  soon he had (2)_______________ left. Of course, when that happened, all his friends disappeared. When he was quite poor and alone, he went to see Nasreddin, who was a kind, clever old man and often helped people when they had trouble.

"My money has been used up and my friends (3) _______________,” said the young man. "What should I do now?"

"Don't worry, young man," answered Nasreddin. "Everything (4) ______________ all right soon again. Wait and you will feel much happier."

The young man was very glad. "Am I going to get rich again then? " he asked Nasreddin.

"No, I didn't mean that," said the old man. "I meant that you would soon get used to being poor and (5) _______________ no friends."
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单项选择题

采煤机停止时应先停（）。

A、水

B、牵引

C、电动机

D、调高泵
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