將下列名詞變?yōu)閺?fù)數(shù)形式。
1. sheep ________ 2. leaf ________ 3. woman ________ 4. foot ________
5. family ________ 6. radio ________ 7. German ________ 8. mouse ________
9. tomato ________ 10. box ________ 11. Frenchman ________ 12. student ________
13. life ________ 14. Chinese ________ 15. watch ________ 16. path ________
17. deer ________ 18. toy ________ 19. child ________ 20. knife ________