Question

-----You _____ here in time. ----Sorry,I was held up by the accident. Aare supposed to have arrived

B.are supposed to arrive C.have supposed to arrive D.supposed to arrive

Answer 1

选A，不春辩定唤指式用了完成时表明动作先发于are的时间；

B.中和森配to arrive指将来的时间
C.have supposed to arrive 是主动语态，错误
D.supposed to arrive 是主动语态，错误

追问

还是有点搞不清A和B 的区别，能详细讲一下吗？谢谢

追答

例如：I have a lot of work to do.这句话中的to do就表示将来要发生的动作，暗含了将来时间的意思。而to have done则表示动作已经完成了。

Answer 2

A

Answer 3

A

Answer 4

B