Puzzle Time - 27

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Across
  1. 1. Second largest city in South Korea.
  2. 4. Students wear this at middle and high school.
  3. 5. Currency used in Europe.
  4. 6. It's grey and you can make houses with it.
  5. 7. Woman who works on an airliner.
Down
  1. 2. Bike with only one wheel.
  2. 3. Go across the railway line using a ________.
  3. 8. An airplane has two of these.