Did you know that it was when the guests had already left______they went on with their discussion.为什么填that、
问题描述：
Did you know that it was when the guests had already left______they went on with their discussion.
为什么填that、
答
你知不知道，当客人们走后，他们又继续他们的讨论。
答
你知不知道,当客人们走后,他们又继续他们的讨论?
Did you know that 后面这个宾语从句是强调句
强调句的结构是 It be +强调部分 that/when (大部分情况下是that when很少用的) +要变的句子的其余部分