have been here 后面可不可以用since

have been here 后面可不可以用since 请问 have been 后面接什么词例如句子three students have been killed so far这个是现在完成时的被动语态么 可不可变成three students have killed so far如果不可为什么 有什么区别have been 后面应该接什么词 改错:Someone have been here You have been here,的have THIS IS THE FIRST TIME THAT YOU HAVE BEEN HERE,__?反义疑问句.反前面 还是 后面 had he been here yesterday,he would attend.为什么是had了,后面是would do而不是would have done i have been here many a how many have you been here I HAVE BEEN HERE SINCE TIME o,i have been here before是什么意思 How long have you been here?----____ the end of last week.正确答案是C,为什么其他的不可,A.In B.ByC.SinceD.At They have been here once.把been换成came怎么样 not only the parents but also their son ______ here for two yearsA.has come B.have been C.has been D.have come可是后面是here 不应该用come么。 i have never been here还是i have never been in here I have been here 与I have been living here一样吗?有点弄不清楚. they have been here since 1988,对1988进行提问,（）（）have they been here? have/has been 后面跟什么词? 英语语法 ...would have been 后面加什么?