英语翻译并说明be done是什么意思用法

英语翻译并说明be done是什么意思用法 to be done是什么意思? to be done的用法 being done 和 be doing ;done ；doing ; be done ;to be done 的用法 need to be done.是什么意思? to be done 和having been done的用法 have been done与be done的区别和用法 be used to have done是什么用法? be sorry to have done的用法 主谓一致：（并说明原因）All that can be done___.A.has been done B.has do what is done cannot be undone是什么意思 to have done,to be done,to have been done,having done在用法上有什么