题目

阅读理解 If you have ever tried to catch a resting butterfly, you know it is surprisingly difficult. A new study helps explain why. Previous research had suggested that a butterfly's overhead wing clap forces the insect forward. Researchers thought the wing clap likely formed a pocket of air that shoots out like a jet(喷气式飞机). But no one had tested that until now. To analyze their flight, they placed six butterflies one at a time inside a wind tunnel which was filled with smoke and then used a laser(激光)to light up the smoke just behind the butterfly. Four high-speed cameras were placed in the tunnel to take photos of the movement of the butterfly and the smoke as the butterfly was taking off. This let the researchers create a 3D picture of that air movement as the insect flapped its wings. They analyzed a total of 25 takeoffs by six butterflies. Each included up to three wing beats after takeoff. The butterflies proved more likely to clap their wings together during the first few wing beats than later in flight. The photos show that forces created by the wings give rise to a flight path. The butterflies rise as their wings move down and shoot forward as their wings move up. Awing clap on takeoff, paired with a quick turn, allowed the butterflies to fly away quickly. They also noticed the wings formed an air pocket just before clapping and that the wings' flexibility and this pocket improved the jet force created by the clap. "The study is exalting, "says Ayodeji Bode-Oke, a mechanical engineer in Charlottesville. That means" we have solved the longtime puzzle about how butterflies fly, and it proves nothing is impossible on the road of scientific research. I can't wait to learn about how the study might inform designs for small flying vehicles." （1） Why was laser used in the experiment? A . To frighten the butterflies into flying. B . To help researchers observe the butterflies. C . To help take clear photos of air movement. D . To guide the butterflies through the smoke. （2） What is the finding of the research according to paragraph 5? A . Butterflies fly forward as wings move down. B . An air pocket forms after butterflies clap wings. C . Butterflies beat wings three times before taking off. D . Upward wing movements help butterflies fly forward. （3） What does the underlined word "exalting" in the last paragraph probably mean? A . Puzzling. B . Exciting. C . Simple. D . Impossible. （4） What can be the best title for the text? A . Why Can Butterflies Fly Like a Jet? B . How Can Butterflies Make Wing Claps? C . How Can Butterflies Make Quick Turns? D . Why Can Butterflies Run Away Quickly? 答案： C D B D

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