我们可以使用地下通道安全地过马路。

We could use the ___subway to cross the road safely.

我开始沿着那条狭窄黑暗的地下通道行走。

I began to walk along that narrow and dark ___subway.

这条地下通道为行人提供了在高速公路下的安全通道。

The ___subway provides a safe passage for pedestrians under the highway.