1.He need not have done it.
他本不需要做这件事.
2.Yet they need not have done.
然而他们没有必要这样做.
3.You need not have done it.
你本来不必做此事.
4.I quitted smokinglast month,but I need not have done so.上个月我把烟戒了,但我本不需要这样做的
5.If you have done your best,you need not feel bad about your failure.即使你一已经努力过,你对于失败便不必懊悔.
6.I do not think I really need (should) have done a break.我想我真的需要（应该）做了了断.