since前用have done 还是have been done

since前用have done 还是have been done 请问：当only用在完成时时,是have only done ,only have done还是 have done only? even 和ever 怎么用 是even have done sth 还是have even done sth since we have done our homework now对吗 What have you done since you returned to China? pretend have done还是pretend to have done? since前到底是用过去式还是现在完成时?Plasitic shopping bags______ no longer free at the supermarkets since June 1st,2008A.were B.will be C.have been D.have应该选哪一个?为什么?这到底是为什么？ will have done 还是will have did? All that can be done __been done.请问该用has还是 have? 强调nothing,由nothing引导的句子前部分要倒装吗?就比如是Nohting I have done还是Nothing have I done 英语翻译本学期第一天起,我经常在图书馆学习英语.since the first day of this semester,I often study English in library.请问这句话翻译的对吗?since之后可以用动词一般现在时吗?还是必须用Have done?since the f have .since did区别have .since have done?eg：I haven’t seen you since I’ve been back.I haven’t seen you since I was back. have done还是be done是被动语态, 应该是not have done 还是 hane not done 请问是have not only done ...but also done ...还是 have not only done ...but also have done ... 英语before用法 before前主语后动词用过去时或将来时+时间段+beforebefore前主语后动词用过去时或将来时+时间段+before还have been +时间段+since 对么?还是其他的? have sth to be done/have sth done?为什么要用have anyting to be done? ---Good morning,can i help you?---I'd likt you to have this package____,madam.应该用have sth.done 还是 have sth.to be done