为了到达这个通风口，他们必须凿穿一堵混凝土墙，当然，必须缓慢而秘密地进行这个工作。

To get there they had to chisel away a concrete cell wall, and, of course, it had to be done slowly and on the QT.

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除进风口以外，如有漏气孔隙，应当堵严，如贴胶布，塞棉花，贴胶水纸等。

In addition to outside air inlet, where gas leakage pores, it should be blocked strict, such as patching, plug of cotton and paste glue paper.

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