书名：新TOEIC必考单字600
页数：p.311 Q16
题目：
Please check in with the receptionist when you arrive. If you were given a referral, please tell the receptionist the name of the doctor who ___________ you.
(A)will refer
(B)did refer
(C)refered
(D)refers
答案：C
疑问:
请问为何答案是选c不是b呢？