1.I'm sorry you've missed the train.It__an hour ago.A.had left B.left 2.She said she ___her mother 3 letters in one month.A.had written B.wrote 3.His brother ___ a football player since he came to this school.A.was B.has been C.had been D.is 我想

1.I'm sorry you've missed the train.It__an hour ago.A.had left B.left 2.She said she ___her mother 3 letters in one month.A.had written B.wrote 3.His brother ___ a football player since he came to this school.A.was B.has been C.had been D.is 我想
1.I'm sorry you've missed the train.It__an hour ago.
A.had left B.left
2.She said she ___her mother 3 letters in one month.
A.had written B.wrote
3.His brother ___ a football player since he came to this school.
A.was B.has been C.had been D.is
我想问的是现在完成时和过去完成时的区别.
以及完成时态是不是不能加具体时间,比如:an hour ago这样的.

1.I'm sorry you've missed the train.It__an hour ago.A.had left B.left 2.She said she ___her mother 3 letters in one month.A.had written B.wrote 3.His brother ___ a football player since he came to this school.A.was B.has been C.had been D.is 我想
1.A 释义：火车走发生在过去（一小时前）的过去,所以应用过去完成时.
2.A 释义：写信发生在她说这件事之前,就是过去的过去,要用过去完成时.
这也是一个间接引语,她写信发生在过去,变为间接引语时,再退一个时态,变为过去完成时.
3.B 释义：只要句中出现Since,要用现在完成时,表示过去的动作持续到现在,并有可能持续下去.