common knowledge and present and past simple

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Across
  1. 2. Largest tropical rainforest in the world
  2. 5. Simple present form of "sleep" for he/she/it
  3. 6. Simple present form of "study" for he/she/it
  4. 10. Franklin on the US hundred dollar bill
  5. 12. Gas humans need to breathe to live
  6. 13. Large, slow-moving mass of ice
  7. 16. Simple past of "cut"
  8. 17. Marine animal with eight arms
  9. 20. Ancient Egyptian stone structure
  10. 21. The largest hot desert in the world
  11. 22. Simple past of "go"
  12. 23. Simple past form of "think"
  13. 24. Simple present form of "go" for he/she/it
  14. 27. Molten rock beneath the Earth's surface
  15. 28. The tallest mountain peak on Earth
  16. 29. Simple past form of "drink"
  17. 30. Ocean that is the largest on Earth
  18. 31. Mountain that erupts with lava
Down
  1. 1. Simple past form of "walk"
  2. 3. Simple past form of "eat"
  3. 4. Preserved remains of an ancient organism
  4. 7. The imaginary line dividing Earth into North and South
  5. 8. Simple past form of "run"
  6. 9. Simple past form of "buy"
  7. 11. The closest planet to the Sun
  8. 14. Tool used for finding magnetic direction
  9. 15. Force that pulls objects toward Earth
  10. 18. Extinct furry elephant-like animal
  11. 19. Simple present form of "write" for he/she/it
  12. 25. Major international sports games held every four years
  13. 26. The capital city of Australia
  14. 29. The hardest natural mineral on Earth