[CET6-阅读]王长喜-六级考试标准阅读(46)*

湖南校园网 www.sunnyol.com
王长喜-六级考试标准阅读(46)湖南校园网 www.sunnyol.com


   You stare at waterfall for a minute or two， and then shift your gaze to its surroundings. What you now see appears to drift upward.湖南校园网 www.sunnyol.com
    These optical illusions occur because the brain is constantly matching its model of reality to signals from the body‘s sensors and interpreting what must be happening—that your brain must have moved， not the other； that downward motions is now normal， so a change from it must now be perceived as upward motion.湖南校园网 www.sunnyol.com
    The sensors that make this magic are of two kinds. Each eye contains about 120 million rods， which provide somewhat blurry black and white vision. These are the windows of night vision； once adapted to the dark， they can detect a candle burning ten miles away.湖南校园网 www.sunnyol.com
    Color vision in each eye comes from six to seven million structures called cones. Under ideal conditions， every cone can “see” the entire rainbow spectrum of visible colors， but one type of cone is most sensitive to red， another to green， a third to blue.湖南校园网 www.sunnyol.com
    Rods and cones send their messages pulsing an average 20 to 25 times per second along the optic nerve. We see an image for a fraction of a second longer than it actually appears. In movies， reels of still photographs are projected onto screens at 24 frames per second， tricking our eyes into seeing a continuous moving picture.湖南校园网 www.sunnyol.com
    Like apparent motion， color vision is also subject to unusual effects. When day gives way to night， twilight brings what the poet T.S. Eliot called “the violet hour.” A light levels fall， the rods become progressively less responsive. Rods are most sensitive to the shorter wavelengths of blue and green， and they impart a strange vividness to the garden‘s blue flowers.湖南校园网 www.sunnyol.com

    However， look at a white shirt during the reddish light of sunset， and you‘ll still see it in its “true” color—white， not red. Our eyes are constantly comparing an object against its surroundings. They therefore observe the effect of a shift in the color of illuminating on both， and adjust accordingly.湖南校园网 www.sunnyol.com
    The eyes can distinguish several million graduations of light and shade of color. Each waking second they flash tens of millions of pieces of information to the brain， which weaves them incessantly into a picture of the world around us.湖南校园网 www.sunnyol.com
    Yet all this is done at the back of each eye by a fabric of sensors， called the retina， about as wide and as thick as a postage stamp. As the Renaissance inventor and artist Leonardo da Vinci wrote in wonder， “Who would believe that so small a space could contain the images of all the universe？”湖南校园网 www.sunnyol.com
    1.Visual illusions often take place when the image of reality is ___.湖南校园网 www.sunnyol.com
    A.matched to six to seven million structures called cones.湖南校园网 www.sunnyol.com
    B.confused in the body‘s sensors of both rods and cones.湖南校园网 www.sunnyol.com
    C.interpreted in the brain as what must be the case.湖南校园网 www.sunnyol.com
    D.signaled by about 120 million rods in the eye.湖南校园网 www.sunnyol.com
    2.The visual sensor that is capable of distinguishing shades of color is called ___.湖南校园网 www.sunnyol.com
    A.cones湖南校园网 www.sunnyol.com
    B.color vision湖南校园网 www.sunnyol.com
    C.rods湖南校园网 www.sunnyol.com
    D.spectrum湖南校园网 www.sunnyol.com
    3.The retina send pulses to the brain ___.湖南校园网 www.sunnyol.com
    A.in short wavelengths湖南校园网 www.sunnyol.com
    B.as color pictures湖南校园网 www.sunnyol.com
    C.by a ganglion cell湖南校园网 www.sunnyol.com
    D.along the optic nerve.湖南校园网 www.sunnyol.com
    4.Twenty-four still photographs are made into a continuous moving picture just because ___.湖南校园网 www.sunnyol.com
    A.the image we see usually stays longer than it actually appears.湖南校园网 www.sunnyol.com
    B.we see an object in comparison with its surroundings.湖南校园网 www.sunnyol.com
    C.the eyes catch million pieces of information continuously.湖南校园网 www.sunnyol.com
    D.rods and cones send messages 20 to 25 times a second.湖南校园网 www.sunnyol.com
    5.The author‘s purpose in writing the passage lies in ___.湖南校园网 www.sunnyol.com
    A.showing that we sometimes are deceived by our own eyes.湖南校园网 www.sunnyol.com
    B.informing us about the different functions of the eye organs.湖南校园网 www.sunnyol.com
    C.regretting that we are too slow in the study of eyes.湖南校园网 www.sunnyol.com
    D.marveling at the great work done by the retina.湖南校园网 www.sunnyol.com
    答案：CADAB 湖南校园网 www.sunnyol.com






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