As has already been pointed out,grammar is not a set of dead rulrs.为什么不能用Which而用Asas代替一整个句子而which也可以啊

Username has already been taken Screen name has already been taken This username has already been used是什么意思 That survey has already been taken. A snow w_ has been posted already Tom as well as his calssmates has been on a package tour to beijing already这句话对吗,还是要用has gone as has been mentioned above... She has been to shanghai already变成否定和疑问句 This registration code has already been used by another user. mike has already been to thebotanical gardens改为一般疑问句 winnie has already been to ocean park改否定句 he has already been to america 变否定句 Payment for this advertising proposal has been already released,翻译! He has been a member of the club already翻译 myhomework has already been fishied改为否定句? _______ has already been pointed out,grammar is not a set of dead rulesa.There b.If c.Such d.As mr.smith____here for there weeks a :has already been b :has already been being这题选哪个?为什么? 用...has/have already been...but...not...yet.造句用...has/have already been...but...not...yet.造句，要三句，