How can we learn from the past?

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Across
  1. 3. process of building roads, buildings, bridges, etc.
  2. 5. farming
  3. 7. an instrument used in scientific study to make very small things look larger
  4. 9. an unpleasant result
Down
  1. 1. to put someone in prison
  2. 2. an act of saying 'No'
  3. 4. the time when an important change takes place
  4. 6. to keep something in good conditions
  5. 8. the act of sailing all the way around the world