2. 外语
  3. As one works with color in a practical or experimental way, one is impressed by two apparently unrelated facts. Color as seen is

As one works with color in a practical or experimental way, one is impressed by two apparently unrelated facts. Color as seen is

admin2005-11-28  98
问题     As one works with color in a practical or experimental way, one is impressed by two apparently unrelated facts. Color as seen is a mobile changeable thing depending to a large extent on the relationship of the color to other colors seen simultaneously. It is not fixed in its relation to the direct stimulus which creates it. On the other hand, the properties of surfaces that give rise to color do not seem to change greatly under a wide variety of illumination colors, usually(but not always)looking much the same in artificial light as in daylight. Both of these effects seem to be due in large part to the mechanism of color adaptation mentioned earlier.
    When the eye is fixed on a colored area, there is an immediate readjustment of the sensitivity of the eye to color in and around the area viewed. This readjustment does not immediately affect the color seen but usually does affect the next area to which the gaze is shifted. The longer the time of viewing, the higher the intensity, and the larger the area, the greater the effect will be in terms of its persistence in the succeeding viewing situation. As indicated by the work of Wright and Shouted, it appears that, at least for a first approximation, full adaptation takes place over a very brief time if the adapting source is moderately bright and the eye has been in relative darkness just previously. As the stimulus is allowed to act, however, the effect becomes more persistent in the sense that it takes the eye longer to regain its sensitivity to lower intensities. The net result is that, if the eye is so exposed and then the gaze is transferred to an area of lower intensity, the loss of sensitivity produced by the first area will still be present and appear as an "afterimage" superimposed on the second. The effect not only is present over the actual area causing the "local adaptation" but also spreads with decreasing strength to adjoining areas of the eye to produce "lateral adaptation". Also, because of the persistence of the effect of the eye is shifted around from one object to another, all of which are at similar brightness or have similar colors, the adaptation will tend to become uniform over the whole eye.
If a person’s eye has been looking at an object in bright sunlight for some time, and then shifts to an object not well lit, we can expect______.
选项 A、a time lag in the focusing ability of the eye
B、some inability to see colors of the latter-named objects until loss of sensitivity has been regained
C、the immediate loss of the "afterimage" of the first object
D、the adaptation in the central area of the eye but little adaptation in the lateral areas to the new intensity level
答案B
解析 本题中，A、C、D三项在文中未被提及。从最后一段可知，B项“直到失去的感觉恢复后才能看见东西”符合文意。因此B项为正确答案。
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