Solve the following crossword puzzle on the basis of your knowledge of the lesson.

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Across
  1. 5. If fire gets out of control it can be very __________
  2. 6. Another term for amazing.
  3. 7. Small fire can be put out with a_____ blanket or a sack.
Down
  1. 1. A particular temperature at which every fuel begins to burn
  2. 2. Another term for discovery.
  3. 3. Who is sitting very still?
  4. 4. Fire is a good servant but a bad _________