Supply the correct forms of the words in brackets.
1. They collected over 1000 (sign) ______ for the petition.
2. The World Health (organize) ______ is an interactional one.
3. My father is working (happy) ______ at the new house.
4. We need many special classes for (handicap) ______ children.
5. There is a big (differ) ____________________ between the new shopping mall and present shopping area.
6. My brother likes acting and outdoor (act) ______.
7. You should fill in this (apply) _____ before the interview.
8. This box is made of (recycle) ______ paper.
9. Are there any (similar) ______ between them?
10. She should say a few words of (explain) ______.
11. Because of the (encourage) ______ of her teacher, she decided to study law.
12. The scouts do the (volunteer) ______ work.
13. His novels have been known (world) ______.
14. (Luck) ______, the barber cut my hair too short.
15. Children need to have a good (educate) ______.
16. The first World (young) ______ Festival was held in Prague in 1974.
17. We will interview only three (apply) ______ for the job.
18. We should save (nature) ______ resources.
19. He's involved in the (organize) ______ of a new club.
20. You should give him some (encourage) ______.
21. Each of my friends has a (differ) ______ character.