When and why he came here ________ yet.A．is not knownB．are not known C．has not

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When and why he came here ________ yet.

A．is not known

B．are not known

C．has not known

D．have not bee

答案

解析

略

举一反三

I wonder how much ________.

A．does the watch cost	B．did the watch cost
C．the watch costed	D．the watch costs

题型：不详难度：| 查看答案

Mary is ________ someone might recognize her.

A．afraid of

B．afraid about

C．afraid that

D．afraid for

题型：不详难度：| 查看答案

________ is no reason for dismissing her.

A．Because she was a few minutes late	B．Owing to a few minutes late
C．The fact that she was a few minutes late	D．Being a few minutes late

题型：不详难度：| 查看答案

They came to the conclusion ________ by a computer.

A．that not all things can be done	B．because of not all things be done
C．being not all things can be done	D．because not all things can be done

题型：不详难度：| 查看答案

Why the explosion occurred was ____the laboratory attendant had been careless.

A．for

B．because

C．since

D．that

题型：不详难度：| 查看答案