2022小學英語語法：need ＂不必做＂和＂本不該做＂

　　didn't need to do表示： 過去不必做某事， 事實上也沒做。

　　needn't have done表示： 過去不必做某事， 但事實上做了。

　　John went to the station with the car to meet Mary， so she didn't need to walk back home.

　　約翰開車去車站接瑪麗，所以她不必步行回家了。

　　John went to the station with the car to meet Mary， so she needn't have walked back home.

　　約翰開車去車站接瑪麗，所以她本不必步行回家了。 (Mary步行回家，沒有遇上John的車。）

　　典型例題

　　There was plenty of time. She ___.

　　A. mustn't have hurried

　　B. couldn't have hurried

　　C. must not hurry

　　D. needn't have hurried

　　答案D。needn't have done. 意為“本不必”，即已經(jīng)做了某事，而時實際上不必要。

　　Mustn't have done 用法不正確，對過去發(fā)生的事情進行否定性推斷應為couldn't have done， “不可能已經(jīng)”。 must not do 不可以（用于一般現(xiàn)在時）。

　　點擊查看更多：更多語法知識

　　奧數(shù)網(wǎng)提醒：

小學數(shù)學題、單元測試、課本同步試題

盡在“奧數(shù)網(wǎng)”微信公眾號