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.
These optical illusions occur because the brain is constantly matching its model of reality to signals from the bodys sensors and interpreting what must be happeningthat 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.
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.
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.
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.
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 gardens blue flowers.
However, look at a white shirt during the reddish light of sunset, and youll still see it in its true colorwhite, 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.
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.
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?
1.Visual illusions often take place when the image of reality is ___.
A.matched to six to seven million structures called cones.
B.confused in the bodys sensors of both rods and cones.
C.interpreted in the brain as what must be the case.
D.signaled by about 120 million rods in the eye.
2.The visual sensor that is capable of distinguishing shades of color is called ___.
A.cones
B.color vision
C.rods
D.spectrum
3.The retina send pulses to the brain ___.
A.in short wavelengths
B.as color pictures
C.by a ganglion cell
D.along the optic nerve.
4.Twenty-four still photographs are made into a continuous moving picture just because ___.
A.the image we see usually stays longer than it actually appears.
B.we see an object in comparison with its surroundings.
C.the eyes catch million pieces of information continuously.
D.rods and cones send messages 20 to 25 times a second.
5.The authors purpose in writing the passage lies in ___.
A.showing that we sometimes are deceived by our own eyes.
B.informing us about the different functions of the eye organs.
C.regretting that we are too slow in the study of eyes.
D.marveling at the great work done by the retina.
第46篇答案:CADAB
小闹钟
意外的发现
每日一词∣交通领域新基建 new infrastructure construction in the transport sector
捉蝴蝶
国际英语资讯:Syrian forces shell rebel-held areas in Idlib, Aleppo: monitor
欧洲疫情卷土重来 年轻人成感染“主力军”
国际英语资讯:U.S. COVID-19 cases surpass 5.4 mln: Johns Hopkins University
国内英语资讯:China calls on intl community to reject U.S. hegemonic interference in 5G cooperation
陪女儿考研的妈妈考上博士!那些重返校园的中年人太励志
卫健委、教育部:秋季开学后中小学生应随身备用口罩
国际英语资讯:Pakistan has defeated terrorism, extremism, says president
国际英语资讯:U.S. equities eke out modest weekly gains amid economic data, stimulus stalemate
爬南山
《习近平谈治国理政》第三卷重要概念汉英对照(三)
国际英语资讯:Chinese Embassy in Poland opposes Pompeos erroneous claims on China
国际英语资讯:New Zealand election to be delayed to Oct. 17 due to COVID-19
World No-Tobacco Day 世界无烟日
国际英语资讯:Moroccos COVID-19 cases surpass 42,000 with 1,472 new infections
国内英语资讯:China welcomes Putins proposal of holding online summit over Iranian nuclear issue
国内英语资讯:U.S. trilateral negotiations subvert intl consensus on nuclear disarmament: Chinese envoy
国际英语资讯:Poland, U.S. sign military agreement
国内英语资讯:China probes polyphenylene ether imports from U.S.
国内英语资讯:Chinas Tibet issues govt bonds on exchange market for first time
国内英语资讯:Chinas Yangtze River sees fourth flood of the year
国内英语资讯:Xi Focus: Xis vision of eco-protection guides Chinas green development
美国“Karen”梗火了……网上人人喊打,这究竟是个什么人设?
全球数百人因新冠错误信息死亡
体坛英语资讯:Murray ousts Ljubicic to reach Wimbledon last 16
国内英语资讯:China Focus: Beijings Xinfadi wholesale market reopens as COVID-19 outbreak ebbs
国际英语资讯:Former CEO of Angola sovereign fund gets five years in jail: supreme court
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |