Sweet tooth什么意思

　　我最害怕看牙医，但是因为有一颗蛀牙让我实在疼痛难忍，所以只好鼓足勇气，到牙医诊所挂号。当医生为我检查的时候，他问我：“Do you have a sweet tooth?”我很无辜地回答：“I had a doughnut this morning before coming here. I brushed my teeth. There is no s...