科目:高中英語 來源: 題型:閱讀理解
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(注視)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(發(fā)展)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(深刻的理解)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.
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
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.
While sleeping, some water animals tend to keep half awake in order to ______.
A.alert themselves to the approaching enemy
B.emerge(浮現)from water now and then to breathe
C.be sensitive to the ever-changing environment
D.avoid being swept away by rapid currents
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
查看答案和解析>>
科目:高中英語 來源:2012-2013學年四川省雅安中學高一上學期入學模擬考試英語試卷(帶解析) 題型:閱讀理解
A good memory is a great help in learning a language. Everybody learns his own language by remembering what he hears when he is a small child, and some children, like boys and girls who live abroad with their parents, seem to learn two languages almost as easily as one. In school it is not easy to learn a second language because the pupils have so little time for it, and they are busy with other subjects, too.
A man’s mind is rather like a camera, but it takes photos not only of what we see but of what we feel, hear, smell and taste. When we take a real photo with a camera, there is much to do before the photo is finished and ready to show to our friends. In the same way there is much work to be done before we can keep a picture forever in our mind.
Memory is the diary that we all carry about with us.
【小題1】We usually begin to learn our own language by ________ it.
A.speaking | B.hearing | C.saying | D.teaching |
A.teacher | B.camera | C.memory | D.family |
A.they are very clever | B.they have good teachers |
C.they have more chances to use these languages | D.they have a better life |
A.the best diary | B.the best camera | C.a great help | D.a beautiful picture |
查看答案和解析>>
科目:高中英語 來源:2008年普通高等學校招生全國統一考試福建卷英語試題 題型:閱讀理解
We have designed all our bank cards to make your life easier.
How to use your NatWest Servicecard
As a Switch card, it lets you pay for all sorts of goods and services, whenever you see the Switch logo. The money comes straight out of your account, so you can spend as much as you like as long as you have enough money (or an agreed overdraft(透支) to cover it. It is also a cheque guarantee(擔保) card for up to the amount shown on the card. And it gives you free access to your money from over 31,000 cash machines across the UK.
How to use your NatWest Chshcard
You can use your Cashcard as a Sulo card to pay for goods and services wherever you see the Solo logo. It can also give you access to your account and your cash from over 31,000 cash machines nationwide. You can spend or withdraw(提取) what you have in your account, or as much as your agreed overdraft limit.
Using your card abroad
You can also use your Servicecard and Cashcard when you’re abroad. You can withdraw cash at cash machines and pay for goods and services wherever you see the Cirrus or Maestro logo displayed.
We take a commission charge(手續(xù)費) of 2.25% of each cash withdrawal you make (up to £4) and a commission charge of 75 pence every time you use Maestro to pay for goods or services. We also apply a foreign-exchange transaction fee of 2.65%.
How to use your NatWest Credit Card
With your credit card you can do the following:
* Pay for goods and services and enjoy up to 56 days’ interest-free credit.
* Pay in over 24 million shops worldwide that display the Maestrocard or Visa logos.
* Collect one AIR MILE for every £20 of spending that appears on your statement(結算單).
(This does not include foreign currency or traveler’s cheques bought, interest and other charges.)
【小題1】If you carry the Servicecard or the Cashcard, _______.
A.you can use it to guarantee things as you wish |
B.you can draw your money from cash machines conveniently |
C.you can spend as much money as you like without a limit |
D.you have to pay some extra money when you pay for services in the UK |
A.£4 | B.£4.5 | C.£5.25 | D.£5.3 |
A.You have to pay back with interest within 56 days. |
B.You will be charged some interest beyond two months. |
C.You can use the card in any shop across the world. |
D.You will gain one air mile if you spend £20 on traveller’s cheques. |
A.play your cards right | B.use your cards abroad |
C.draw cash with your cards | D.pay for goods with your cards |
查看答案和解析>>
科目:高中英語 來源:2015屆陜西長安一中高一下期期末考試英語卷(解析版) 題型:單項填空
—Why don't we take a little break?
—Didn't we just have________?
A.it B.that C.one D.this
查看答案和解析>>
科目:高中英語 來源:2010年高考二輪復習英語語法強化訓練非謂語動詞 題型:單項填空
-Do you feel like ________there or shall we take a bus.
-I’d like to walk . But since there isn’t much time left ,I’d rather you _______a taxi.
A.walking, hire |
B.to walk , hire |
C.walking ,hired |
D.to walk. hired |
查看答案和解析>>
湖北省互聯網違法和不良信息舉報平臺 | 網上有害信息舉報專區(qū) | 電信詐騙舉報專區(qū) | 涉歷史虛無主義有害信息舉報專區(qū) | 涉企侵權舉報專區(qū)
違法和不良信息舉報電話:027-86699610 舉報郵箱:58377363@163.com