You ________ see the dentist when you have a toothache.

You ________ see the dentist when you have a toothache.
A、may
B、need
C、should
D、can
【正确答案】：C
【题目解析】：may可能，也许；need需要；should应该；can能够句意：当你牙疼时你应该去看牙医。