Henry can’t attend the party _______at Tom’s house at present because he is preparing for the speech at the party _______ at Marie’s house tomorrow.

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When we returned from our holidays, we found everything _______. What _______ while we had been away?

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A．changed; had happened

B．changing; happened

C．had changed; has happened

D．was changing; happened

--How do you deal with the disagreement between the company and the customers?

--The key ________ the problem is to meet the demand ________ by the customers.

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It was not until then _______ I came to know that knowledge comes from practice.

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The building ______ and more than 300 people ______ in the fire.

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A．was destroyed; lost their lives

B．ruined; lost their lives

C．was damaged; lost their lives

D．was ruined; lost lives

There aren’t many seats left for this concert; you’d better come _______ to _______ that you have one today.

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--Oh, it's you! I ________ you.

--I've just had my hair cut, and I'm wearing new glasses.

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It is difficult for us to learn a lesson in life ________ we've actually had that lesson.

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In China, rubbish, such as plastic bags and boxes ________ “white pollution” is becoming a serious problem.

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The professor spoke slowly enough to make his speech easy ________.

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