隧洞的英文：
tunnel

The engineers sank a tunnel into the ground.
工程师们在地下挖了个隧道。

The exit of the tunnel is concealed.
地道的出口开在隐秘的地方。

A tunnel was to be blasted through the mountains.
一条隧道要被炸开，穿山而过。

They drove a tunnel through a hill.
他们通过小山挖一隧道。

The roof of the tunnel fell in.
隧道顶部塌了下来.。