Scientists ______ SARS for several months before a major discovery was made in t

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Scientists ______ SARS for several months before a major discovery was made in the field.

A．had been studying	B．have been studying
C．have studied	D．are studying

答案

解析

略

举一反三

The task _____ more difficult than we expect.

A．proved to

B．proved us

C．was proved

D．proved

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Some teenagers _______ their health because they often expose themselves to so many electric products.

A．have damaged

B．are damaging

C．damaged

D．will damage

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30. The subway __________in our city, and I’m sure there will be fewer traffic jams in the future.

A．is building

B．is built

C．is being built

D．will build

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What I said and did at your house last night_________just between you and me.

A．is

B．are

C．have been

D．had been

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The price_________recently. I wonder whether it will remain so.

A．was going up

B．went up

C．has gone up

D．has been going up

题型：不详难度：| 查看答案