It is certain that we are able to reach the top of the mountain before night () 使用fall
问题描述:
It is certain that we are able to reach the top of the mountain before night () 使用fall
答
It's certain that we are able to reach the top of the moutain before night falls.
在黑夜降临前,未发生但是将会发生.用一般现在时falls表将来.