It was 1920 ______ regular radio broadcasts began. A．whileB．whenC．thatD．since

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It was 1920 ______ regular radio broadcasts began.

A．while

B．when

C．that

D．since

答案

解析

考查定语从句。when 指先行词1920 。

举一反三

He hasn’t got any hobbies---_______ you call watching TV a hobby.

A．If

B．Unless

C．When

D．Since

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Scientists say it may be one year or so ________ it is possible to test the new medicine on human patients.

A．when

B．after

C．before

D．since

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He looks so weak and pale ________ suffering from a serious illness.

A．as if

B．as long as

C．now that

D．even if

题型：不详难度：| 查看答案

There is no doubt _________ the world climate has been changing in recent years.

A．that

B．what

C．if

D．whether

题型：不详难度：| 查看答案

children believe they can succeed, they will never become totally independent．

A．If

B．Though

C．Unless

D．When

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