To explain what they have seen, the scientists build a theory about the way ________ things happen and the causes and effects.

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He made the headmaster so angry that he couldn't avoid ________.

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________ known to everybody, the moon travels round the earth once every month.

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He sent me an e-mail, ________ to get further information.

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________ poor in English, I'm afraid I can't make myself ________.

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________ the idiom, he looked it up in the dictionary.

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Victor apologized for ________ to inform me of the change in the plan.

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During the ________ season, there are millions of visitors traveling ________ areas abroad.

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________ in the south of Jiangsu Province, my hometown is a paradise for life.

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If you feel a sudden urge ________ a poem, write down as quickly as you can.

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