三、阅读表达。
阅读下面短文，简略回答问题。
Chinese eating rules have a long history and there are many important eating manners in China. Among them, there are some key ones to follow.
First, it’s not polite to start eating before everyone sits down. You also should let the elders eat first to show your respect.
Second, you should use chopsticks(筷子) rightly. Don’t point at others or knock the plates and bowls with them. If you want to serve(服务) food to others, it’s better to use serving chopsticks.
Third, don’t make too much noise when eating. It’s better to chew(咀嚼) with your mouth closed to show good manners. And don’t speak when your mouth is full of food.
Fourth, don’t reach(到达) across the table for food. You should wait for the turntable(转盘) to bring it to you.
18. When is it not polite to start eating in China?
19. Who should start eating first?

20. What shouldn’t you do with chopsticks?

21. How should you chew when eating?

22. How many rules does the writer give about eating manners in China?

18. Before everyone sits down.
19. The elders.
20. You shouldn’t point at others or knock the plates and bowls.
21. You should chew with your mouth closed.
22. Four.