I'll never forget the happpy days_we spent together.

问题描述:

I'll never forget the happpy days_we spent together.
A.with which
B.in which
C.when
D./

D
spend可以直接加时间,表示花费多长时间做某事,不用加介词.这里是度过的意思.
这是个定语从句,用that或which引导(that/which可以省略),不能用介词,故不选AB,when=in which,故也不选C