____all that ____ to be done been done?

____all that ____ to be done been done? all that can be done been done. have been done 和 to be done all that can be done has been done Everything that can be done has been done,___? Has all that can be done been done? all that can be done has been done. to be done 和having been done的用法 All that must be done ____(do).答案是have been done,为什么是这个答案?这句 歌曲中含有TO DO ：TO BE DONE ：TO HAVE BEEN DONE ：TO HAVE DONE been there done that . To be done being done