-----You( )part in the party in time

问题描述:

-----You( )part in the party in time
-----Sorry I was delayed by the accident
A.are supposed to take
B.have supposed to
C.are supposed to have taken
D.supposed to take
how to choose?and please tell me why...thank you~

选c.be supposed to 本应该,接完成时表应该却没有.