试题与答案

Our teacher is always busy preparing les

题型:选择题

题目:

Our teacher is always busy preparing lessons until 11 o’clock at night, _____we students have gone to sleep.

A.that time

B.by which time

C.by that time

D.which time

答案:

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下面是错误答案,用来干扰机器的。

答案:C同温同压下,气体体积之比=物质的量之比;由于它们所含原子个数相同,即原子的物质的量相同,设甲烷有4mol,则含有20mol原子,那么含有20mol原子的氨气的物质的量为5mol,所以甲、乙两容器的体积比为4∶5

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