what hav u been doing的been是干吗的?

what have u been doing的been是什么时态? Have been doing 的被动语态是? will have been doing和have been doing的区别 to having been doing 和having been doing 的区别 has been doing 的用法 have been doing 的用法, has been doing的问题, what have you been doing what you have been doing THE STUDENTS HAV BEEN PREPARING THEIR LESSON的问题. what u been up too? have been do和have been doing的不同