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    The writer is probably . A. a cheerful young bachelor B. a keenly observant father C. an appreciative fond mother D. a spoiled naughty kid C Birds that are half-asleep-with one brain hemisphere alert and the other sleeping-control which side of the brain remains awake, according to a new study of sleeping ducks. Earlier studies have documented half-brain sleep in a wide range of birds. The brain hemispheres take turns sinking into the sleep stage characterized by slow brain waves. The eye controlled by the sleeping hemisphere keeps shut, while the wakeful hemisphere’s eye stays open and alert. Birds also can sleep with both hemispheres resting at once. Decades of studies of bird groups led researchers to predict extra alertness in the end-of-the-row sleepers which tend to be attacked more easily. Sure enough, the end birds tended to watch carefully on the side away from their companions. Ducks in the inner spots showed no preference for gaze direction. Also, birds napping at the end of the line depend on single-hemisphere sleep, rather than total relaxation, more often than inner ducks did. Turning 16 birds through the positions in a four-duck row, the researchers found that compared with 12 percent for birds in internal spots, outer birds half-asleep during some 32 percent of napping time. “We believe this is the first evidence for an animal behaviorally controlling sleep and wakefulness at the same time in different regions of the brain, the researchers say. The results provide the best evidence for a long-standing assumption that single-hemisphere sleep evolved as creatures scanned for enemies. The preference for opening an eye on the lookout side could be widespread, he predicts. He’s seen it in a pair of birds napping side-by-side in the zoo and in a single pet bird sleeping by a mirror. The mirror-side eye closed as if the reflection were a companion and the other eye stayed open. Useful as half-sleeping might be, it’s only been found in birds and such water animals as dolphins, whales, and seals. Perhaps keeping one side of the brain awake allows a sleeping animal to surface occasionally to avoid drowning. Studies of birds may offer unique insights into sleep. Jerome M. Siegel of the UCLA says he wonders if birds’ half-brain sleep “is just the tip of the iceberg. He supposes that more examples may turn up when we take a closer look at other species. 【查看更多】

     

    题目列表(包括答案和解析)

    What Is a Boy?

    Between the innocence of babyhood and the seriousness of manhood we find a delightful creature called a “boy”. Boys come in different sizes, weights, and colors, but all boys have the same belief: to enjoy every second of every minute of every hour of every day and to fill the air with noise until the adult males pack them off to bed at night.

    Boys are found everywhere – on top of, under, inside of, climbing on, swinging from, running around, or jumping to this and that! Mothers spoil them, little girls hate them, older sisters and brothers love them, and God protects them. A boy is TRUTH with dirt on its face，BEAUTY with a cut on its finger, WISDOM with chocolate in its hair, and the HOPE of the future with a snake in its pocket.

    When you are busy, a boy is a trouble – maker and a noise. When you want him to make a good impression, his brain turns to jelly or else he becomes a wild creature bent on destroying the world and himself with it.

    A boy is a mixture – he has the stomach of a horse, the digestion of stones and sand, the energy of an atomic bomb, the curiosity of a cat, the imagination of a superman, the shyness of a sweet girl, the brave nature of a bull, the violence of a firecracker, but when you ask him to make something, he has five thumbs on each hand.

    He likes ice cream, knives, saws, Christmas, comic books, woods, water (in its natural habitat), large animals, Dad, trains, Saturday mornings, and fire engines. He is not much for Sunday schools, company, schools, books without pictures, music lessons, neckties, barbers, girls, overcoats, adults, or bedtime.

    Nobody else is so early to rise, or so late to supper. Nobody else gets so much fun out of trees, dogs, and breezes. Nobody else can put into one pocket a rusty knife, a half eaten apple, a three-foot rope, six cents and some unknown things.

    A boy is a magical creature – he is your headache but when you come home at night with only shattered pieces of your hopes and dreams, he can mend them like new with two magic words, “Hi, Dad!”

    46. The whole passage is in a tone(调子) of _________.

    A. humor and love        B. respect and harmony

    C. ambition and expectation  D. confidence and imagination

    47. What does the underlined sentence in Para 4 probably mean?

    A. He has altogether five fingers.  B. He is slow, foolish and clumsy.

    C. He becomes clever and smart.   D. He cuts his hand with a knife.

    48. According to the writer, boys appreciate everything in the following EXCEPT _________.

    A. ice cream          B. comic books     

           C. Saturday mornings    D. Sunday schools

    49. What does the writer feel about boyhood?

    A. Curious.     B. Tiring.       C. Delightful. D. Unsafe

    50. The writer is probably __________________________.

    A. a cheerful young bachelor              B. a keenly observant father     

    C. an appreciative fond mother            D. a spoiled naughty kid

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    What is a Boy?

    Between the innocence of babyhood and the seriousness of manhood we find a delightful creature called a “boy”. Boys come in different sizes, weights, and colors, but all boys have the same belief: to enjoy every second of every minute of every hour of every day and to fill the air with noise until the adult males pack them off to bed at night.

         Boys are found everywhere--- on top of, under, inside of, climbing on, swinging from, running around, or jumping to this and that! Mothers spoil them, little girls hate them, older sisters and brothers love them, and God protects them. A boy is TRUTH with dirt on its face, BEAUYTY with a cut on its finger, WISDOM with chocolate in its hair, and HOPE of the future with a snake in its pocket.

         When you are busy, a boy is a trouble-maker and a noise. When you want him to make a good impression, his brain turns to jelly or else he becomes a wild creature bent on destroying the world and himself with it.

         A boy is a mixture--- he has the stomach of a horse, the digestion of stones and sand, the energy of an atomic bomb, the curiosity of a cat, the imagination of a superman, the shyness of a sweet girl, the brave nature of a bull, the violence of a firecracker, but when you ask him to make something, he has five thumbs on each hand.

         He likes ice cream, knives, saws, Christmas, comic books, woods, water (in its natural habitat), large animals, Dad, trains, Saturday mornings, and fire engines. He is not much for Sunday schools, company, schools, books without pictures, music lessons, neckties, barbers, girls, overcoats, adults, or bedtime.

    Nobody else is so early to rise, or so late to supper. Nobody else gets so much fun out of trees, dogs, and breezes. Nobody else can put into one pocket a rusty knife, a half eaten apple, a three-foot rope, six cents and some unknown things.

    A boy is a magical creature---he is your headache but when you come home at night with only shattered pieces of your hopes and dreams, he can mend them like new with two magic word, “Hi, Dad!”

    61. The whole passage is in a tone of _______ .

    A. humor and love                   B. respect and harmony   

    C. ambition and expectation            D. confidence and imagination

    62. What does the underlined sentence in Pare 4 probably mean?

    A. He has altogether five fingers.       B. He is slow, foolish and clumsy.

    C. He becomes clever and smart.       D. He cuts his hand with a knife.

    63. According to the writer, boys appreciate everything in the following EXCEPT ___________.

    A. ice cream      B. comic books     C. Saturday mornings   D. Sunday schools

    64. What does the writer feel about boyhood?

    A. Curious.       B. Tiring.          C. Delightful.          D. Unsafe.

    65. The writer is probably ________ .

    A. a cheerful young bachelor           B. a keenly observant father

    C. an appreciative fond mother         D. a spoiled naughty kid

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