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.

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。

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Cut cured concrete pipe sections with saw or chisel, and cement sections together to form odd shaped fittings.

用锯子或凿子一起切割固化混凝土管段以及水泥部分，形成奇形接头。

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