pair (sb) off
If a group of people pair off, they divide into pairs in order to do something, and if you pair them off, you divide them into pairs.
两人一组结成对;把(一组人)分成几对
The students paired off to practise their conversational skills.
学生们两人一组进行会话技巧练习。
After dinner the boys and girls paired off and went to the dance.
会餐后， 男女青年们成对成对地去跳舞。
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