have/has been doing sth. 1.现在完成进行时 当后面接有一段时间的词时,或是加表示时间的词时,可以用现在完成时.如果这件事现在还在持续或还在做,则可用 现在完成进行时. 如:I have been skating for 4 hours. I have finished my homework. 2.现在完成时的被动语态. 后接动词的过去分词. 如:The building has been built for 5 years.
第2个回答 2019-08-18
have/has后面加been的是现在完成时的被动语态 如:the homework has been finished by me.=i have finished the homework.