Question

I ______ Peter with his work, but I had a lot of things to do myself.

A．must have helped	B．should have helped
C．needn’t have helped	D．can’t have helped

Answer 1

B

試題分析：本題的關(guān)鍵詞是but后面的句中使用了一般過去時(shí)，說明本句表示的是對過去的虛擬。對過去情況的虛擬使用“情態(tài)動(dòng)詞+have done”的形式。Must have done一定做了某事；should have done本應(yīng)該做某事，實(shí)際上卻未做；needn’t have done本不需要做，實(shí)際上去做了；can’t have done不可能做某事；句義：我本應(yīng)該幫助Peter做他的工作，但是我有很多自己的事情要做。AD兩項(xiàng)并沒有比賽虛擬語氣，只是對過去情況的推測。C項(xiàng)語義不搭配。根據(jù)句義說明B正確。