needn’t have done與didn’t need to do用法區(qū)別

needn’t have done 主要表示某事已經(jīng)做了，但后來覺得沒必要去做，因此常含有責(zé)備或遺憾之意；didn’t need to do 則不具體表明某事是否做了(即可能做了也可能沒有做，此用法中的need為實(shí)意動(dòng)詞)：

I got up early, but I needn’t have done so, because I had no work to do that morning. 我起床起得很早，但我本來不必起那么早的，因?yàn)槲夷翘煸缟蠜]什么事做。

I didn’t need to get up early this morning, so I stayed in bed until 9 am. 今天早上我不必早起，所以我一直睡到上午九點(diǎn)鐘才起床。

若沒有特定的上下文，有時(shí)可能有歧義：

I didn’t need to go the office yesterday.

(1) 我昨天無需去那兒。(所以沒去)(=I didn’t have to go there yesterday.)

(2) 我昨天本來不必去那兒的。(但我卻去了)(=I needn’t have gone there yesterday.)