You seeadentistwhenyouhaveatoothache.A. mayB. needC. shouldD. can

问题补充：

You seeadentistwhenyouhaveatoothache.

A. may

B. need

C. should

D. can

答案：

A. may

B. need

(答案→)C. should

D. can

解析：情态动词辨析。may可以；need需要；should应该；can可能，能。句意：当你牙疼时，你应该去看牙医。故选C。