Nancy ______ another city since she graduated, but last year she ____ back home.
A. has gone to; has come
B. went to; came
C. has been to; has come
D. has been in; came
【答】可以用排除法得出D是正确答案:在but连接的分句中,时间状语是 last year ,谓语动词只能用一般过去时,不能用现在完成时,所以,A 和C选项是错误的。如果 since 引导时间状语从句,主句的谓语动词必须是延续性动词,went 是非延续性动词,所以选项B也是错误的。