have finished 为什么要用现在完成时?

have finished 为什么要用现在完成时? Have you finished your homework Yes,I __it in twenty minutes.选 A.have finished 还是 B.finished 为什么? I won't lend you the book before I have finished it.为什么用have finished _____ the work we went home.A.Having finished B.Having been finished C.Have finished D.Have been finished 选哪个?为什么? I have finished my homework.可否这么说 I finished my homework.为什么 have you finished already?是什么句型.为什么要finished already这么放,不能倒过来吗? have you finished already?为什么不用have you finished yet?have you finished already?为什么不是have you finished yet?我老师说过already 用于肯定句中,yet用于否定句和一般疑问句 I thought you would have finished by now.为什么不是I think you would have finished by now? You shall borrow the book when I have finished reading it为什么要用have finished,这里是有什么语法呢,finished不可以吗 --Have you finished your composition already,Jack?--Yes,I___it with in half an hour.A.have finished C.finished 为什么选C不选A? 回答是finished还是have finished? I have finished my homework.When _____you_____it?为什么填didi,finish?用一般过去式不是要用finished吗? -Will you come to my office when you ____your work? -Sure 为什么不填finished而要用have finished finish变延续性动词是什么?是finished还是be over 为什么我们英语书上写的是we have finished finish or finished?When ____(finish),the book will probably have 500 pages.为什么不是it finish 而是 finished they will have finished work on the new stadium.为什么要用finished work on ,而不用finished working on 记得finish后面跟的是动名词吖... You must have the paper _______ by the end of this month.A.finish B.to be finished C.finished D.being finished为什么B不可以? I will go to see you when you finish/finished/have finished the course是哪个,为什么如果这里只给你finish/finished呢？是选一个