There comes a time in every man"s life_____.

问题描述:

There comes a time in every man"s life_____.
A that he needs to think
B when he has to think
C therefore he has to work
D THEN HE WILL NEED IT

很明显这是一个定语从句,因此排除没有先行词的C和D,在A和B中,a time表示时间点,先行词应该用when,所以选B.