| A.His bad habit | B.His bad teeth |
| C.Not smiling | D.Eating too much sugar |
| A.they don’t like smiling |
| B.they think they are ugly |
| C.their teeth are not beautiful |
| D.they can’t open their mouths |
| A.A dentist can tell you how to improve your bad teeth. |
| B.A dentist can help you to take care of your bad teeth. |
| C.A dentist can tell you how to brush your teeth. |
| D.Both A and B |
| A.not smile often |
| B.laugh all the time |
| C.neither smile nor laugh |
| D.smile and even laugh often |
| A.Either 20 or 30 times a day |
| B.Between 7 and 15 times a day |
| C.Around 30 times a day |
| D.Only 30 times a day |