17. The chairs and desks are made of w .

16. People throw 1 into the river and make it really dirty.

15. The medicine should be taken t a day after meals.

14. Nobody knew what to say and they just sat there in s .

21. In the daytime my mother worked hard. She fell a  soon last night.

13. My e brother is not very nice to me. He always refuses to let me watch my favorite TV show.

12. I am always n when I have to make a speech.

11. There is going to b a meeting today.

10. He i  me to a party yesterday.

9. This is your book,and m is over there.