Almost _______ by man, the Antarctica is the only continent in the world that has kept its primitive ecological balance.

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A. untouched

B. being untouched

C. to be untouched

D. have been untouched

They helplessly watched the rocket ________ away by the flood.

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--What do you think made Mary so upset?

-- ________ her new bicycle.

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I'm thankful to him for that advice，__________ I owe all my success．

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I'm tired today so I want to go to bed early．Please don't call me after eight p．m．because I __________．

A．will have slept

B．will be sleeping

C．had slept

D．am asleep

It's too late to go to the football match now；________ it's beginning to rain．

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They are good friends．It is no _________ that they always help each other．

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So loudly ________ that even in the next room could hear him．

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Yesterday evening I ________ a book on science．I'll try to finish it today．

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Who can you turn to for help，it not __________?

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