i'm sorry ___ you about it before.
问题描述:
i'm sorry ___ you about it before.
a.not to tell
b.not to have told
为什么不选a?
答
b.not to have told
have done 意思是本来应该做,却没有做
我很抱歉,我本来应该提前告诉你,却没有.
祝好!