而且至少在办公室安装一个烟雾探测器。

And at least one smoke detector should be properly installed in the office.

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办公室天花板下聚集了一层蓝色的香烟烟雾。

The office had collected a blue layer of cigarette smoke near the ceiling.

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办公室天花板下聚集了一层蓝色的香烟烟雾。

The office had collected a blue layer of cigarette smoke near the ceiling.

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