I have no idea what _____when I was asleep.A is happening B did happen C happened D was happened

问题描述:

I have no idea what _____when I was asleep.A is happening B did happen C happened D was happened

C.
happen是不及物动词,没有被动语态.这句话的意思是:我不知道我在睡觉时发生了什么.