1.sportswoman-sportswomen
2. valley- valleys
3. thief- thieves
4. mouse- mice
5.sheep- sheep
6.wolf- wolves
7.deer- deer
8. shelf- shelves
9. potato- potatoes
10. brush - brushes
11. berry- berries
12. child - children
13. radio- radios
14. tooth- teeth
15. Englishman- Englishmen
16. hero- heroes
17. video- videos
18. wife- wives
19. goose- geese
20.photo- photos