不认识认识

drop in 英 [drɔp in] 　美 [drɑp ɪn]

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drop in

phrase. (使)落进；(使)往里坍塌：　 phrase. 偶然(或顺便)走访(或访问)(on)；逐渐进入：　 phrase. [口语](有选择地)加入；愿意(或决心)参加：　

There was a marked drop in temperature.　气温显著下降。

The director dusted his staff down about the drop in their efficiency.　主任责备他的工作人员工作效率下降。

1. There was a marked drop in temperature.

气温显著下降。
2. The director dusted his staff down about the drop in their efficiency.

主任责备他的工作人员工作效率下降。
3. Remember to lag the water pipes with some cloth when there is a drop in temperature.

气温下降时记住要用一些布裹住水管。