They sound the same

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Across
  1. 1. Likes to chase mice
  2. 3. going somewhere
  3. 4. Man's best friend
  4. 5. opposite of hi
  5. 8. Large marsupial
  6. 9. Flying mammal
Down
  1. 2. more than one
  2. 3. in addition
  3. 4. opposite of night
  4. 5. to purchase
  5. 6. Has a trunk
  6. 7. opposite of sad