One way is to try to design a completely air-tight train, like an airplane cabin.

一种方法是试着设计一个完全密闭的火车，像飞机舱一样。

youdao

One way is to try to design a completely air-tight train, like an airplane cabin.

一种方法是试着设计一个完全密闭的火车，像飞机舱一样。

youdao