Never swim there, so I suppose it is better to be safe ________.

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－Have you decided already?

－Yes, I ________ at once.

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________ to somebody, a British person often shake hands with the stranger.

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“Why ________ you always ________ the same silly mistake?”said the teacher angrily.

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The heavy box ________ there by the porter three days ago is still there.

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________ we know of life on earth suggests ________ life will arise wherever the proper conditions exist.

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By next autumn they ________ for ten years.

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The doctor was not sure about the operation, but the patient insisted that the operation be done ________ it was a success.

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There are 200 night clubs in the city, and you don't often see ________ that is empty.

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Nothing helps success more than ________ what you are doing.

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