写出下列单词的复数形式。
1.dog_____ 2.puppy_____ 3.lion_____ 4.baby_____ 5.cat_____	6.piglet_____ 7.horse_____ 8.calf_____ 9.goose_____ 10.joey_____	11.duckling_____ 12.hen_____ 13.mouse_____ 14.child_____ 15.knife_____

1. dogs 2. puppies 3. lions4. babies 5. cats
6. piglets 7. horses 8. calves 9. geese 10. joeys
11. ducklings 12. hens 13. mice 14. children 15. knives