Look at the ten statements for this part. You will hear a man talking about "The Wright Brothers ". Decide whether you t

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问题     Look at the ten statements for this part.
    You will hear a man talking about "The Wright Brothers ".
    Decide whether you think each statement is right(R), wrong(W)or not mentioned(NM).
The powered aircraft was built to learn how propellers work.
Look at the ten statements for this part.
    You will hear a man talking about the Wright Brothers.
    Decide whether you think each statement is right(R), wrong(W)or not mentioned(NM).
    In 1899, the Wright Brothers designed their first aircraft: a small, biplane glider. The Wright Brothers spent a great deal of time observing birds in flight. They noticed that birds soared into the wind and that the air flowing over the curved surface of their wings created lift. Birds change the shape of their wings to turn and maneuver. They believed that they could use this technique to obtain roll control by warping, or changing the shape, of a portion of the wing.
    Over the next three years, Wilbur and his brother Orville designed a series of gliders which were flown in both unmanned and piloted flights. They recognized that control of the flying aircraft would be the most crucial and hardest problem to solve.
    Following a successful glider test, the Wrights built and tested a full-size glider. In 1900, the Wrights successfully tested their new 50-pound biplane glider in both unmanned and piloted flights. In fact, it was the first piloted glider. Based upon the results, the Wright Brothers planned to refine the controls and landing gear, and build a bigger glider.
    In 1901, the Wright Brothers flew the largest glider ever flown. Many problems occurred. The Wrights reviewed their test results and decided to build a wind tunnel to test a variety of wing shapes and their effect on lift. Based upon these tests, they planned to design a new glider with a 32-foot wingspan and a tail to help stabilize it.
    During 1902, the brothers flew numerous test glides using their new glider. With successful glides to verify their wind tunnel tests, the inventors planned to build a powered aircraft. After months of studying how propellers work the Wright Brothers designed a motor and a new aircraft. The craft weighed 700 pounds and came to be known as the Flyer.
    After two attempts to fly this machine, one of which resulted in a minor crash, Orville Wright took the Flyer for a 12-second, sustained flight on December 17,1903. This was the first successful, powered, piloted flight in history.
    In 1904, the first flight lasting more than five minutes took place on November 9. The Flyer II was flown by Wilbur Wright.
That is the end of Part 3. You now have 20 seconds to copy your answers onto the Answer Sheet.

选项 A、Right
B、Wrong
C、Not Mentioned

答案B

解析
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