They stood beside the station in the rain ________ goodbye to their friends.

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It is generally considered unwise to give a child ________ he or she wants.

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I wish I ________ to talk this over with Mr. Zhang when he was here last night.

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You should never ________ when driving a car.

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You are free ________ come and go as you please.

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________ you do, you should carry it to the end．

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----I just heard that the tickets for tonight's show have been sold out.

----Oh, no! ________.

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A．I was looking forward to that

B．It doesn't matter

C．I knew it already

D．It's not at all interesting

There's ________ virus going round the office.

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I'm immune ________ smallpox (天花) as a result of vaccination (牛痘).

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I can send him a note ________ the internal mail system.

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