29.The telephone ________ four times in the last hour,and each time it ________ for my roommate.
29.The telephone ________ four times in the last hour，and each time it ________ for my roommate.
A.has rung; was B.has been ringing; is
C.had rung; was D.rang; has been
可我认为应该选C。因为last hour过去了，应该用过去完成时呀！