since.ago能否用于现在完成时态

since.ago能否用于现在完成时态 since years ago用于什么时态 for yet ago before since分别用于什么时态 since用于什么时态 since用于什么时态 since...ago加完成时态吗?完成时态的标志是什么? 在现在完成时态 since 引导的句子中,主句的谓语动词必须用持续动词吗?He has left here since two years ago.He has been away since two years ago.是两个都对,还是有错? His grandpa died three years ago 改为现在完成时态 ever since用于什么时态? The rain stopped twenty minutes ago.怎么改成现在完成时态还有如meet,set out,hear from 如何改为持续性动词用于现在完成时 since before ,since ago 语法解析1 请问 在现在完成时态里面 since 5 years before ,since 5 years ago 那个对?还是都正确,讲解下.2 写个句子The air conditioner was turned on 5 hours ago.The air conditioner has been turned on si ﹙1﹚Since then he▁﹙work﹚at this factory 一定要用现在完成时态?since只能用用现在完成时态?since 不能用于其他时态吗?﹙2﹚There are ▁interesting books that I don't know ▁to read 选项上只有so many ；which ﹙1﹚Since then he▁﹙work﹚at this factory 一定要用现在完成时态?since只能用用现在完成时态?since 不能用于其他时态吗?﹙2﹚There are ▁interesting books that I don't know ▁to read 选项上只有so many ；which in the past few years是用于过去完成时态还是现在完成时态? since…ago表示什么时态 since用于什么时态 so far用于什么时态 after可不可以用于完成时态? since能否与ago是连用哦