| A mysterious phenomenon is the ability
of over-water migrants to travel on course. Birds, bees, and other species can
keep track of time without any sensory cues from the outside world, and such
"biological clocks" clearly contribute to their "compass sense." For example,
they can use the position of the Sun or stars, along with the time of day, to
find north. But compass sense alone cannot explain how birds navigate the ocean:
after a flock traveling east is blown far south by a storm, it will assume the
proper northeasterly course to compensate. Perhaps, some scientists thought,
migrants determine their geographic position on the Earth by celestial
navigation, almost as human navigators use stars and planets, but this would
demand of the animals a fantastic map sense. Researchers now know that some
species have a magnetic sense, A. migration over land requires a simpler explanation than migration over water does B. the means by which animals migrate over water are complex and only partly understood C. the ability of migrant animals to keep track of time is related to their magnetic sense D. knowledge of geographic location is essential to migrants with little or no compass sense [单项选择]
An Interesting Phenomenon Animals seem to have the sense to eat when they are hungry and they do not eat more than their bodies need. It has been demonstrated that rats will, when given a choice over a period of time, prefer water with vitamins to water without vitamins even though there is no difference in taste or smell between the two water bottles. When a fragrant flavor was added to the vitamin-enriched fluid, the rats did seem to develop a taste for it and kept drinking it, even after the vitamins were switched to the clear water. In time, however, they broke the habit and went back to where the necessary vitamins were. In a classic experiment, babies of 6 to 12 months old were placed in a cafeteria feeding arrangement, with a wide selection of baby food before them. They were given whatever food they pointed to or appeared interested in. We are told that at first they showed some unusual eating patterns, but that over a pe A. encourage rats to drink vitamin-enriched water B. find out rats preference in flavor C. test whether rats know which drink is good for them D. demonstrate that vitamins are tasteless [填空题]
Language Change The phenomenon of language change probably attracts more public notice and more (1) (disapprove) than any other linguistic issue. There is a widely held belief that change must mean (2) (deteriorate) and decay. Older people observe the casual speech of the young and conclude that standards have fallen appreciably. It is understandable that many people dislike change, but it is (3) (wise) to condemn all linguistic (4) (modify). It is often felt that contemporary language illustrates the problem at its worst, but this belief is shared by every generation. There are indeed cases where linguistic change can lead to problems of unintelligibility and (5) (ambiguous), and if change is too rapid there can be major communication problems. But as a rule, the parts of language which ale undergoing change at any given time are (6) (relative) small in comparison 我来回答: 提交
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