1. man
2. fox
3. family
4. mobile phone
5. baby
6. person
7. radio
8. dictionary
9. teacher
10. watch
11. bus
12. fish
13. photo
14. tomato
15. woman
16. wife
17. body
18. fly
19. colour
20. mother-in-law
To check the answers, click on the picture below or on the link above, and you'll be directed to Joanne's webpage, who also offers an explanation of the rules governing the spelling rules of plurals.
