For thousand of years men couldn’t fly. It was 1. ______ too difficult. Birds are able to fly on their

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问题     For thousand of years men couldn’t fly. It was                    1. ______
   too difficult. Birds are able to fly on their                      2. ______
   wings. It is very easy of them to fly.                             3. ______
   But men haven’t got wings. The first planes                        4. ______
   were gliders — planes without engine.                             5. ______
   The first plane with a engine was the Flyer.                       6. ______
   Two brothers, Wilbur and Orville Wright, building                  7. ______
   it. In December 17th, 1903, Orville lay on the bottom wing         8. ______
   of his plane and start the engine.                                 9. ______
   The Flyer was able take off and rose 10 feet and flew 120          10. ______
   feet. This was a great moment in the history of flying.

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