1.Why didn't you watch the show yesterday?
Because i ____it before.
A.had watched 因为是在Yesterday前,已经看过.表示过去的过去,用过去完成时.
2.Mary hasn't phone us yet.what____to her?
B has happened 到现在为止,MARY没有给我们打电话,到现在为止她发生了什么事吗
3.There is a crossing.We don't know_____
B which street to turn to 这是个十字路口,不知道选哪一条路,在一定范围内选