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

I close my eyes and can still hear her—the little girl with a ___1___ so strong and powerful we could hear her halfway down the block. She was a(n)  ___2___ peasant who asked for money and ___3___ gave the only thing she had——her voice. I paused outside a small shop and listened. She brought to my mind the ___4___ of Little Orphan Annie. I could not understand the words she  ___5___, but her voice begged for ___6___. It stood out from the noises of Arbat Street, pure and impressive, like the chime of a bell. She sang ___7___ an old-style lamp post in the shadow of a building, her arms extended and ___8___ thrown back. She was small and of unremarkable looks. Her brown hair ___9___ the bun(发髻) it had been pulled into, and she occasionally reached up to ___10___ a stray piece from her face. Her clothing I can’t recall. Her voice, on the other hand, is ___11___ imprinted in my mind.

I asked one of the translators about the girl. Elaina told me that she and hundreds of others like her throughout the ___12___ Soviet Union add to their families’ income by working on the streets. The children are unable to ___13___ school, and their parents work fulltime. These children know that the consequence of an ___14___ day is no food for the table. Similar situations occurred during the Depression(萧条) in the United States, but those American children were ___15___ shoeshine boys of the ___16___. This girl was real to me.

When we walked past her I gave her money. It was not out of pity ___17___ rather admiration. Her smile of ___18___ did not interrupt her singing. The girl watched us as we walked down the street. I know this because when I looked back she smiled again. We ___19___ that smile, and I knew I could never forget her courage and ___20___ strength.

1. A. will B. strength      C. voice  D. determination

2. A. American       B. Chinese      C. Japanese     D. Russian

3. A. in return B. in turn       C. by hand      D. in silence

4. A. voice      B. image C. story   D. looks

5. A. said B. murmured  C. used    D. sang

6. A. attention B. love    C. help    D. mercy

7. A. across     B. from   C. under  D. from underneath

8. A. hands     B. feet     C. head   D. face

9. A. fell out   B. escaped      C. did up D. tied to

10. A. remove B. tear     C. cut off       D. dress

11. A. never    B. permanently      C. occasionally       D. sometimes

12. A. latter    B. rich    C. former       D. great

13. A. attend   B. finish  C. leave   D. enjoy

14. A. unhappy      B. unsatisfied  C. unusual      D. unsuccessful

15. A. faced    B. real     C. faceless      D. visible

16. A. twenties       B. thirties       C. forties D. teens

17. A. and      B. while  C. but     D. or

18. A. contempt     B. pity    C. bitterness    D. thanks

19. A. stopped B. shared C. won    D. exchanged

20. A. full      B. inner   C. brave  D. fighting

At the age of 13，I visited a doctor with my parents. As I sat in the examining chair，the doctor looked into my 　31　.“She did inherit (继承) it，”he said with coldness.“You need to be prepared. There is no 　32　 for this disease.”

My father 　33　 a gene which，in most cases，results in blindness. I’d inherited the gene. He gradually 　34　 his eyesight and so did I. At last we were both 　35　 blind—he was fifty-seven years old，　36　 I was only twenty-eight.

My world 　37　 as the darkness fell，　38　 the dreams my husband and I had for us and for our three little boys. But 　39　 I tried to find some hope and 　40　，my eyes were opened to a new realization.

My father had 　41　 me not just failing eyesight，but an example of 　42　 in the face of hardships as well. We were all living in Bolivia in 1964 when he decided to 　43　 the family to America. He worked tirelessly to 　44 the right of living in the US.

Alone in the States，he 　45　 his helplessness and lack of fluency in English. He managed to rent a small apartment，and nine months later，sent airline tickets for my mom，my brother and me.

Decades later，　46 an American citizen，I look back at what he'd shown me. He set an example proving that determination is important to success. His 　47　 taught me valuable lessons for my own path in the darkness.

I did the same as I stepped into a 　48　 world. I fulfilled (完成) my own 　49　 as a wife，mom，Sunday school teacher and Spanish interpreter. What I inherited from my father helped me to 50　 my life in a whole new light.

1.A.mouth           B.eyes          C.ears          D.throat

2.A.solution         B.reason         C.excuse          D.cure

3..A.carried            B.spread            C.infected      D.raised

4.A.damaged         B.lost         C.recovered     D.gained

5.A.rapidly         B.nearly         C.completely       D.terribly

6.A.though              B.but               C.so                D.since

7.A.broke down      B.broke off     C.broke away        D.broke out

8.A.realizing           B.sharing      C.disturbing        D.destroying

9.A.when            B.before         C.unless           D.until

10.A.honour         B.beauty            C.strength      D.failure

11.A.handed         B.rewarded      C.given         D.taught

12.A.contribution       B.determination C.challenge     D.honesty

13.A.move           B.settle            C.arrange           D.send

14.A.enjoy           B.declare          C.apply         D.win

15.A.accepted       B.admitted      C.overcame      D.met

16.A.as                 B.like          C.for            D.to

17.A.knowledge      B.journey           C.situation          D.event

18.A.cruel          B.inner             C.modern         D. dark

19.A.promises       B. hopes            C. roles            D. changes

20.A.touch          B. end          C. save           D. see

I close my eyes and can still hear her—the little girl with a ___1___ so strong and powerful we could hear her halfway down the block. She was a(n) ___2___ peasant who asked for money and ___3___ gave the only thing she had—her voice. I paused outside a small shop and listened. She brought to my mind the ___4___ of Little Orphan Annie. I could not understand the words she ___5___, but her voice begged for ___6___. It stood out from the noises of Arbat Street, pure and impressive, like the chime of a bell. She sang ___7___ an old-style lamp post in the shadow of a building, her arms extended and ___8___ thrown back. She was small and of unremarkable looks. Her brown hair ___9___ the bun(发髻) it had been pulled into, and she occasionally reached up to ___10___ a stray piece from her face. Her clothing I can’t recall. Her voice, on the other hand, is ___11___ imprinted in my mind.