A large fish was slowly swimming through the water, its tail __ back and forth like the pendulum of a clock．

A．swung

B．was swinging

C．was swung

D．swinging

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参考答案

D。一条大鱼在水里慢慢游过，尾巴像钟摆一样来回摆动。
考查非谓语动词。逗号之前为主句，具备完整的主谓结构；逗号后没有连词，但是有主语，因此应该是一个独立主格结构；swing为不及物动词，和tail间为主动关系，所以使用现在分词。

1 They are teachers and don't realize __ to start and run a company．

A．what it takes

B．what takes it

C．what they take

D．what takes them

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2 The millions of calculations involved, __ by hand, would have lost all practical value by the time they were finished．

A． had they been done

B．having been done

C．they had been done

D．they were done

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3 When you have finished that book, don't forget to put it on the bookshelf, ．__ ?

A．do you

B．will you

C．don't you

D．won't you

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