He was about to go to bed ____ there was a knock on the door.

问题描述:

He was about to go to bed ____ there was a knock on the door.
空中填什么?能不能说说填的词有什么相应的知识点?

只能填写when 因为这是高中的重要短语,以前的版本现在书上没有,但是经常考,sb be about to do sth ---when sth happen.某人正要做某事 突然(就在那时)另一件事情发生了.此处的when相当于 at that time ,不能用whil...