大学教育新东方网 > 大学教育 > 专四专八 > 备考辅导 > 专业八级 > 改错 > 文章正文

2012英语专八改错练习(10)

分享到:

2012-03-07 15:21  作者:  来源:可可英语  字号:T|T

  【练习】

  You stare at waterfall for a minute or two, then shift your gaze to its surrounding. What you now see appears to drift upward. You __1

  are board a train in a busy station when suddenly another train next __2

  to your starts moving forward. __3

  For a fraction of a second you feel that your train has lurched backward. These optical illusions occur because the brain is constantly matching its model of reality to signals from the body’s sensors and interpret what must be happening – that your train __4

  might have moved, not the other; that downward motion is now __5

  normal, so a change from it must be perceived as upward motion.
The sensors that make this magic are two kinds. __6

  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 burnt __7

  ten miles away. Colorful vision in each eye comes from six to seven __8

  million structures called cones. Under ideal conditions, every cone can “see” the entire rainbowspectrum of visible colors, but one type of cone is most sensitive to red, another to green, the third to __9

  blue. By monitoring how many wavelength of light affects the different cones, a connected ganglion cell can determine its “color” and relay that data brainwork. Rods and cones send their messages pulsing an __10

  average 20 to 25 times per second along the optic nerve.

热点课讯

精彩问答

提问