Unit21《Human Biology》(Lesson 1)ppt-北师大版高二下
Unit21《Human Biology》(Lesson 1)ppt-北师大版高二下第3页

Discuss in pairs and answer the following questions.

1. What do you think of chewing gum? Is it good or bad for you? 2. Do you or your friends /family buy it? Why? 3. What do you do after chewing it?