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问题 选择题

两种物质不论以什么质量比混合，只要混合物的质量一定，充分燃烧时产生的水的量总为定值，这组混合物是                                                   （   ）

A．乙炔和丁炔

B．乙烷和丁烷

C．苯和甲苯

D．乙炔和苯

答案

答案：D

符合题意的烃类应该具有相同的最简式，故而乙炔和苯（最简式都为CH）符合题意。

选择题

— What do you think of Jim's schoolwork?

— His schoolwork is better than ______ in his class. [ ]

A.any student's

B.any other student's

C.the other student

D.other student'

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单项选择题

The purpose ( ) my coming here is to inquire about possibilities of establishing trade relations with your company.

A．with

B．of

C．for

D．in
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