写出下列各词的过去式。
1. fall __________________
2. help __________________
3. play __________________
4. eat __________________
5. look __________________
6. go __________________
7. hurt __________________
8. break __________________
9. see __________________
10. want __________________
11. like __________________
12. walk __________________
13. talk __________________
14. jump __________________
15. shop __________________
16. am __________________
17. are __________________
18. work __________________
19. point __________________
20. study __________________
