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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 if 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. The present selection has apparently been preceded by some explanation of ______.
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More than three million years ago, our ancestors were already on the march, rising on two legs to search for food, seek greener lands and, above all, to grow in body and brain. Let’s meet some of them:1. Australopithecus afarensisThey had ape-like faces and their brains were a third the size of modem humans’ brains. They lived 3-3.9 million years ago. Fossils were found in Ethiopia in 1974.2. Paranthropus boiseiCovered with fur, they had strong arms and gorilla-like faces. They lived 1-2.5 million years ago. Fossils were found in Tanzania in 1959.3. Homo habilisHomo habilis, which actually means "handy man", was the first species to make and use primitive stone tools. They lived 1.6-2.2 million years ago. Fossils were found in Tanzania in 1960.4. Homo erectusWith skeletons very similar to those of modern humans, they were probably the first to use fire. They lived 30,000-1.8 million years ago. Fossils have been found in Africa and Asia since 1893.5. Homo heidelbergensisThey were skilled hunters who used spears to kill animals. Their bodies were similar to ours, although more muscular and larger boned. They lived 200,000-500,000 years ago. Fossils have been found in Ethiopia, Germany, France and Spain since 1921.6. Homo NeanderthalTheir brains were at least as large as those of the average modem humans, while their smaller bodies helped them deal with cold climates. They lived 30,000-230,000 years ago. Fossils have been found in France and Iraq since 1856. Which of the following lived earliest on the earth()
Directions: Write 200～250 words to comment on the topic given below. Use the proper space on the ANSWER SHEET. Topic: The More I Learn, the More Ignorant I Find Myself to Be
I climbed the stairs slowly, carrying a big suitcase, my father following with two more. By the time I got to the third floor, I was (36) and at the same time feeling lonely. Worse still, Dad (37) a step and fell, sending my new suitcases (38) down the stairs. "Damn!" he screamed, his face turning red. I knew trouble was ahead. Whenever Dad’s face turns red, (39) !How could I ever (40) him to finish unloading the car (41) screaming at me or making a scene in front of the other girls, girls I would have to spend the (42) of the year with Doors were opening and faces were peering out (探出), as Dad walked (43) close behind. I felt it in my bones that my college life was getting off to a bad start.(44) the room quickly," I thought. "Get him into a chair and to calm down." But (45) , would there be a chair in Room 316 Or would it be an empty room(46) I turned the key in the lock and (47) the door open, with Dad (48) complaining about a hurting knee or something. I put my head in, expecting the worst. But to my (49) , the room wasn’t empty at all! It had furniture, curtains, a TV, and even paintings on the walls.And there on a well-made bed sat Amy, my new roommate, dressed neatly. Greeting me with a nod, she said in a soft voice, "Hi, you must be Gori." Then, she (50) the music and looked over at (51) . "And of course, you’re Mr. Faber," she said, (52) . "Would you like a glass of iced tea" Dad’s face turned decidedly (53) before he could bring out a "yes".I knew (54) that Amy and I would be (55) and my first year of college would be a success. 36().
M: I’ll have these shoes. Please tell me how much I owe you.W: They are＄40 a pair and three pairs make a total of ＄120. But today we offer a 10% discount. How much does the man have to pay()
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