In class, you must concentrate your attention ________ the lesson.

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He is tired after the long travel. He needs ________ a rest.

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We go to school from Monday to Friday. We have a rest ________ weekends.

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-- Why were you late this morning?

-- It was _________I overslept.

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A computer is ________ CPU, main board and some other parts.

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Many clouds in the“sky. ________ it's going to rain.

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I ________ see films when I was a child because I lived in a mountain village.

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Sometimes, ________ is a good choice for a person.

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--Look! A dog lies over there.

--Don't go near it. It ________ bite you.

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-- Tom came back from Los Angles yesterday.

-- Did he? I didn't hear it ________ .

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