Mainliner
n. 主干线列车
🗣️ 情景例句
You really must have your wits about your when dealing with such people.
跟这类人打交道，你必须格外警觉。
Slowly, mountains are worn away by the wind.
山体逐渐被风化了。
it is quite reasonable to regard the sea floor as the basic form of the crust of the earth,
因此完全有理由把海床看作地壳的基本模壳，