Singular and Plural: If the word is singular make it plural. If it's plural, make it singular

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Across
  1. 1. cities
  2. 5. monkey
  3. 8. boss
  4. 10. day
  5. 11. hero
  6. 14. woman
  7. 16. story
  8. 17. fish
  9. 18. watch
  10. 19. finch
Down
  1. 2. tooth
  2. 3. box
  3. 4. mice
  4. 6. knife
  5. 7. shelf
  6. 9. moose
  7. 12. pheasants
  8. 13. boy
  9. 15. name
  10. 18. wolves