to be done 被动语态 The mouse was killed by me.老鼠被我杀了.
have been done 被动语态,完成时态 The mouse have been killed by me.老鼠已经被我杀了.
have been doing 现在完成进行时态 I have been studying since this afternoon.
我从这个下午就开始学.（现在还在学）