You are supposed to have taken part in the party in time.

问题描述:

You are supposed to have taken part in the party in time.
这里为什么与有用to have done

不定式啊!be surppose to我不懂什么语境下用to have doneto have done 应用在主动和已经完成的情况下那么you are supposed to take part in the party in time 与原先句子 有什么区别?be suppose to do应该某事 相当于should第一个相当于should have done 本应该做某事没做哦,谢谢