Learning how to fly took nature millions of years of trial and errorbut a winged robot has cracked it in only a few hours, using the same evolutionary principles. To begin with, the robot just twitched and jerked erratically. But, gradually, it made movements that gained height. At first , it cheated simply standing on its wing tips was one early short cut. After three hours, however, the robot abandoned such methods in favor of a more effective flapping technique, where it rotated its wings through 90 degrees and raised them before twisting them back to the horizontal and pushing down. The robot had metre-long wings made from balsa wood and covered with a light plastic film. Small motors on the robot let it move its wings forwards or backwards, up or down or twist them in either direction. A computer program fed the robot random instructions, at the rate of 20 per second, to test its flapping abilities. Each instruction told the robot either to do nothing or to move the wings slightly in the various directions. 1.Which of the following is NOT true of what is mentioned about the winged robot in the second paragraph? B. The two professors of CUT tested whether the winged robot could learn to fly. D. The two professors of CUT tried to find out if the robot could fly by itself. A. It rotated its wings through 90 degrees. C. It was twitched and broke down. 3.Which of the following is nearest to Peter Bentleys view on the winged robot? B. The winged robot did not have a mortor. D. The robot could fly if it were lighter. A. Two vertical rods. B. A movement detector. 5.What does the process appearing in the last paragraph refer to? B. Sending instructions to the robot. D. All the above.
美国习惯用语-第246讲:to play with fire
美国习惯用语-第236讲:high and dry/dry up
美国习惯用语-第244讲:free and easy
美国习惯用语-第248讲:to get to the botto
美国习惯用语-第245讲:to blow one´s own&nb
美国习惯用语-第233讲:tax-and-spend-liberal
美国习惯用语-第255讲:smoke and mirrors
美国习惯用语-第196讲workaholic
美国习惯用语-第227讲:Give One a Break/Break&n
美国习惯用语-第231讲:Give Somebody the Hook
美国习惯用语-第219讲:Touch Base/o Lunch
美国习惯用语-第220讲:Birds of a feather
美国习惯用语-第224讲:Butterfingers
美国习惯用语-第202讲:One for the books
美国习惯用语-第225讲:Like Greased Lightning
美国习惯用语-第234讲:Redneck/McCarthyite
美国习惯用语-第249讲:There´s no such thin
美国习惯用语-第201讲:Sunday best
美国习惯用语-第232讲:Pick Up the Tab/Go
美国习惯用语-第213讲:short and sweet
美国习惯用语-第223讲:Bread and butter
美国习惯用语-第230讲:Right on the Mark
美国习惯用语-第198讲:Cut a deal
美国习惯用语-第228讲:Break the News/Break the
美国习惯用语-第256讲:to go up in smoke
美国习惯用语-第247讲:half-baked/half-hearted
美国习惯用语-第200讲:Honeymoon
美国习惯用语-第239讲:fair and square/ fair&nb
美国习惯用语-第212讲:Over the long haul
美国习惯用语-第204讲:Bad-mouth
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