have .since did区别have .since have done?

have .since did区别have .since have done? have done for/since和have been doing for/since区别 have done 和 had done 和since的搭配 since we have done our homework now对吗 have done……since的一个问题谢谢 Since I have seen you may have done might have done区别 have done、 have been done的区别 will have done 还是will have did? would rather did 与 would rather have done 的区别? 英语翻译“how long it has been since i have done something" 最好结合情 Susan must have done quite well in the exam since she seems