Birds that are half-asleep — with one brain hemisphere (半球) alert(警觉) and the other sleeping — control which side of the brain remains awake, according to a new study of sleeping ducks.
Earlier studies have recorded 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(注视) direction.
Also, birds napping (打盹) 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 inner 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 developed over time 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.
【小题1】According to the passage, birds often half sleep because ______.

Birds that are half-asleep — with one brain hemisphere (半球) alert(警觉) and the other sleeping — control which side of the brain remains awake, according to a new study of sleeping ducks.

    Earlier studies have recorded 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(注视) direction.

    Also, birds napping (打盹) 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 inner 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 developed over time 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.

1.According to the passage, birds often half sleep because ______.

    A. they have to watch out for possible attacks

    B. their brain hemispheres take turns to rest

    C. the two halves of their brain are differently organized

    D. they have to constantly keep an eye on their companions

2.What is implied about the example of a bird’s sleeping in front of a mirror?

    A. An imagined companion gives the bird a sense of security.

    B. Birds prefer to sleep in pairs for the sake of their security.

    C. The phenomenon of birds napping in pairs is widespread.

D. A single pet bird enjoys seeing its own reflection in the mirror.

3.It can be inferred that _______.

A. Birds never sleep with both hemispheres resting at once.

B. Inner ducks depend on single-hemisphere sleep, rather than total relaxation, as often as birds napping at the end of the line do

C. It is not the first time for scientists to research on birds’ half-brain sleep 

D. Birds hardly sleep without a companion

4.By saying “just the tip of the iceberg”, Siegel suggests that _______.

    A. half-brain sleep has something to do with icy weather

    B. the mystery of half-brain sleep is close to being solved

    C. most birds living in cold regions tend to be half sleepers

    D. half-brain sleep may exist among other species

Birds that are half-asleep — with one brain hemisphere (半球) alert(警觉) and the other sleeping — control which side of the brain remains awake, according to a new study of sleeping ducks.
Earlier studies have recorded 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(注视) direction.
Also, birds napping (打盹) 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 inner 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 developed over time 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.

1. 1.

   According to the passage, birds often half sleep because ______.

   1. A.
      they have to watch out for possible attacks
   2. B.
      their brain hemispheres take turns to rest
   3. C.
      the two halves of their brain are differently organized
   4. D.
      they have to constantly keep an eye on their companions
2. 2.

   What is implied about the example of a bird’s sleeping in front of a mirror?

   1. A.
      An imagined companion gives the bird a sense of security.
   2. B.
      Birds prefer to sleep in pairs for the sake of their security.
   3. C.
      The phenomenon of birds napping in pairs is widespread.
   4. D.
      A single pet bird enjoys seeing its own reflection in the mirror.
3. 3.

   It can be inferred that _______.

   1. A.
      Birds never sleep with both hemispheres resting at once.
   2. B.
      Inner ducks depend on single-hemisphere sleep, rather than total relaxation, as often as birds napping at the end of the line do
   3. C.
      It is not the first time for scientists to research on birds’ half-brain sleep
   4. D.
      Birds hardly sleep without a companion
4. 4.

   By saying “just the tip of the iceberg”, Siegel suggests that _______.

   1. A.
      half-brain sleep has something to do with icy weather
   2. B.
      the mystery of half-brain sleep is close to being solved
   3. C.
      most birds living in cold regions tend to be half sleepers
   4. D.
      half-brain sleep may exist among other species

Birds that are half-asleep—with one brain hemisphere (半球) 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.

66. According to the passage, birds often half sleep because ______.

       A. they have to watch out for possible attacks  B. their brain hemispheres take turns to rest

       C. the two halves of their brain are differently structured

       D. they have to constantly keep an eye on their companions

67. What is implied about the example of a bird’s sleeping in front of a mirror?

       A. An imagined companion gives the bird a sense of security.

       B. Birds prefer to sleep in pairs for the sake of their security.

       C. The phenomenon of birds napping in pairs is widespread.

D. A single pet bird enjoys seeing its own reflection in the mirror.

68. While sleeping, some water animals tend to keep half awake in order to ______.

A. alert themselves to the approaching enemy B. emerge from water now and then to breathe

       C. be sensitive to the ever-changing environment

       D. avoid being swept away by rapid currents

69.  It can be inferred that ----------------.

A. Birds never sleep with both hemispheres resting at once.

B. Inner ducks depend on single-hemisphere sleep, rather than total relaxation, as often as

birds napping at the end of the line do

C. It is not the first time for scientists to research on birds’ half-brain sleep 

D. Birds hardly sleep without a companion

70. By saying “just the tip of the iceberg”, Siegel suggests that ______.

       A. half-brain sleep has something to do with icy weather

       B. the mystery of half-brain sleep is close to being solved

       C. most birds living in cold regions tend to be half sleepers

       D. half-brain sleep may exist among other species

完形填空（共20小题；每小题1.5分，满分30分）

阅读下面短文，从短文后所给各题的四个选项（A、B、C和D）中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。

As the hot tears rolled down her cheeks, I knew I had asked the wrong question. The ___21___reverberated(回荡)in my mind: Widowed or divorced? I looked into the lady’s __22___, now dampened （使潮湿）with the __23___ tears my words had caused.

    “ Well, you could call me widowed,” she replied. “ My husband ___24___ five months ago .”

    “ I am so ____25___ ,” I mumbled. “ I need it to fill out your credit application.”

    “Don’t worry about it, honey,” she ____26___. “if I never thought about it, I would not ___27____ the love and the memories we shared. Even after 50 years of ___28____ ,each passing moment would bring a deeper meaning to the word love. Now, trust me, I know how ____29___ that sounds. We had our share of challenging times, but in the end ____30___ of that mattered.”

Unsure of what to say, I laughed ___31___ . I picked up the phone to relay her information. After finally completing the credit application, I ____32____ to find myself riveted（固定） to the lady’s face again.

Her eyes began to sparkle ___33___ she continued in a heart-to-heart way. I couldn’t believe someone could open up to a perfect stranger, but it was not my place to ___34____ . I enjoyed listening to her just as much as she ___35___ having somebody to talk to.

“ Have you ever been ____ 36___?” she  asked.

I couldn’t help but ___37____. “Ah, no.” I replied. “I’m only 16.”

“Sixteen?” she murmured. “That’s a great age, an age of ____38____. There’s so much worth learning.”

She then spoke in a whipser, “Never take anyone for granted. If you are in ____39___ with someone, let it known. Otherwise, life may pass you by. Don’t spend your life angry . The ridiculous arguments which you think are important won’t even be remembered in a short time.”

Then, she hugged me and thanked me for letting her talk. As she turned to walk away, I could see that tears still hung in her eyes, but the smile that lit her face was amazing. After that,    I have never seen that woman again, but her words of inspiration still live in me. At that time, the words were only little bits of advice. Now, ___40___, they are the words which I try to live by, words that will always remind me of my special friend.

A. tunes          B.whistles              C. songs            D. words

A. eyes           B. hands               C. ears             D. arms

A. grateful        B. miserable            C. happy           D. sweet

A. failed          B. worked              C. died            D. retired

A. sorry           B. lucky               C. anxious         D. gloomy

A. encouraged      B. explained           C. persuaded        D. comforted

A. understand      B. remember           C. experience       D. enjoy

A. teaching        B. struggle             C. marriage         D. life

A. foolish         B. terrible              C. mysterious       D.wonderful

A. few            B. all                 C. some            D. none

A. loudly          B. nervously           C. bravely          D. bitterly

A. attempted       B. began              C. turned           D. went

A. as             B. because             C. before           D. until

A. comment       B. surprise             C. doubt            D. criticize

A. avoided        B. appreciated          C. imagined          D. considered

A. blamed        B. interviewed          C. married           D. employed

A. laugh          B. sigh                C. cry              D. complain

A. success        B. wonder              C.failure            D. lessons

A. peace          B. love                C. agreement        D. harmony

A.but            B. so                  C. however          D.although