We______her letter last week.We don't know what has happened to her.
问题描述：
We______her letter last week.We don't know what has happened to her.
A.must receive
B.must have received
C.oughted to receive
D.ought to have received
感觉是虚拟语气,但是B和D有本应该的意思吗?
答
确实是需要你语气.本句意思是“我们本来上个礼拜就应该收到她的信.（现在）我们不知道她出了什么事.”must have done sth 指的是“一定做过某事”,是对过去动作的肯定推测； ought to have done sth 指的是“本来应该做某事 （但却没做）.所以这题选的是D.