Crossword puzzle - unusual friendships

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Across
  1. 1. to stay with someone so that they are not alone
  2. 4. unhappy because you are not with other people
  3. 6. someone who you spend a lot of time with or go somewhere with
  4. 8. someone you have never met before
  5. 9. argue with someone, and stop being friendly with them
Down
  1. 2. someone with no brothers and sisters
  2. 3. the activity of talking and doing things with other people
  3. 5. to form a good relationship with somebody quickly
  4. 6. knowing somebody very well and liking them very much
  5. 7. a member of your family