John knocked at the door for nearly five minutes____his wife opened it.A．whenB．b

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John knocked at the door for nearly five minutes____his wife opened it.

A．when

B．before 　　

C．until 　　

D．as

答案

解析

略

举一反三

Sally worked late in the evening to finish her report _____ her boss could read it first thing next morning.

A．because 　　

B．so that 　　

C．before 　　

D．or else

题型：不详难度：| 查看答案

The idea of fish being able to produce electricity strong enough to light a lamp is almost unbelievable, _____ several kinds of fish are really able to do this.

A．therefore

B．and 　　　　

C．then 　　　　

D．but

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______ they live in the same house, we would no trouble finding them.
---But as traveling salesmen as well as seasonal herdsmen and farmhands, as you know, they move house _______ many of the Americans who live on wheels.

A．As far as; as often as	B．As well as; as well as
C．As long as;;as often as	D．As long as ; as far as

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_____ he thought he was helping us with the work , he was actually in the way.

A．Because 　　　

B．If 　　　　　　

C．Although 　　　

D．When

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The question came up at the meeting _____ we had not enough money to do the research.

A．whether

B．if 　　　　　

C．that 　　　　

D．what

题型：不详难度：| 查看答案