香港药品保质期怎么看:如何理解:They have done more than they can do for the party.

如何理解:They have done more than they can do for the party. have done 如何翻译 英语选择题求教：They have done ------ more work this week than last week. They have done all they could "to help" him.为什么是"to help"? meant to have done They had done that before have sth done 为什么用done呢 have sth done的用法 have done表示现在完成式？ have sth done是什么语态？