Question

I was about to leave my office _____i was told that the president would visi

I was about to leave my office _____i was told that the president would visit our company.
A. while B when C as D if
为什么不能选C

Answer 1

这里只能用when.
be about to do ...when 意思是”正要去做某事这时……”

下面讲讲为什么不能选C

因为when可以和延续性动词连用，也可以和短暂性动词连用；
而as只能和延续性动词连用。

本题中"leave"和"told"都不是连续性动词，
所以不能用------as-------

祝你学习进步~

Answer 2

be about to do when。。。是固定搭配。正要做某事的时候。。。
as 有正如的意思，与句子意思不相符

希望能帮到你~！

Answer 3

虽然as 有当什么时候的意思，但这是固定搭配，be about to do when