Old medieval dungeons had trapdoors laid underneath stones.

早先中世纪地牢的石头地面下都有暗门。

Moreover, this scheme does not use the discrete logarithm with trapdoors.

此外，本方案没有使用陷门离散对数。

There are trapdoors, sliding doors, double doors, stage doors, prison doors, glass doors.

还有活板门、拉门、双折门、舞台门、监狱门、玻璃门等。

There are trapdoors in the ground floor for performers to rise from the ground or fly to the heaven.

一层的地板是活动的，演员在演神话剧时，可以突然从地下冒出来，或者飞升上天。