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.

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 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

根据短文内容，从短文后的选项中选出能填入空白处的最佳选项。选项中有多余选项。

The Dark Age of Greece

【小题】Among early civilizations, we call the low points "dark ages", because civilizations often dropped to such a low level that it is hard to get an accurate picture of their history during these periods. During a dark age, a civilization may not have produced monuments, statue, or other objects which we use to learn about early civilizations.

One' of the most important dark ages was the dark age of Greece,which lasted from about 1100 BC to 900 BC. Prior to-that-time,Greece had a highly advanced society called the Mycenaean civilization. The Mycenaeans were a trading civilization1.In fact, the Mycenaean civilization was so important that when it collapsed in the 12th centuryBC,most other civilizations in the region collapsed as well.The next 200 years are like a blank page to  historians and we know very little about this period.2.The collapse of the Mycenaeans brought an end to writing in the area, and thus an end to the written records historians rely on.

The little that we know about this period has been learned from archaeology. It seems that civilization became much less advanced. The pottery from this period is much simpler and less artistic. This suggests that there was lack of wealthy people to buy higher quality products. 3.   This would suggest a large decrease in population, possibly due to a widespread lack of food and consequent starvation.

Sometime around 800 BC, the Greeks began to emerge from this dark age, most probably due to the influence of other civilizations. They had lost their early writing system, but began to use the writing system of the Phoenicians at this time.4.Over the next 300 years, their civilization continued to rise, and their dark age was forgotten.

A.Many civilizations undergo a series of high points and low points during their history.

B.Many early civilizations underwent dark ages, but Greece never recovered from its dark age.

C.They began constructing larger cities and trading with their neighbors again.

D.Another interesting point is that most of the large cities of earlier time periods appear to have been abandoned in favor of much smaller settlements.

E.Many pieces of evidence suggest that there was a huge increase in population during the dark age of Greece.

F.and they did much to spread their culture across the eastern Mediterranean.

G.One major reason for this is that writing basically stopped.

Happiness is U-shaped, for we are happier at the start and end of our lives but hit a slump when we are middle-aged, British and US researchers say.

Economists from the University of Warwick, central England, and from Dartmouth College, New Hampshire, looked at data on the mental health of two million people from 80 countries.

In Britain, the probability of depression for men and women peaks at around 44 years of age, Warwick University said in a press release.

In the United States, though, ________________________between men and women. Among women, unhappiness peaked at around the age of 40, whereas among men, it was about 50.

But the U-shape of happiness is constant around the world, and mid-life depression occurs regardless of marital status（婚姻状况）, changes in job or income.

The study appears in Social Science & Medicine, published by the Dutch publishing house Elsevier.

"It happens to men and women, to single and married people, to rich and poor, and to those with and without children.” said co-author Andrew Oswald.

One possibility may be that people realize they won't achieve many of their ambitions at middle age. The researchers said.

Another reason could be that after seeing their fellow middle-aged peers begin to die, people begin to value their own remaining years and embrace life once more.

But the good news is that if people make it to aged 70 and are still physically fit, they are on average as happy and mentally healthy as a 20-year old.

"For the average persons in the modern world, the dip in mental health and happiness comes on slowly, not suddenly in a single year," Oswald said. "Only in their fifties do people emerge from this low period.”

1. Which sentence in the passage is the closest in meaning to the following one?

There are chances that the middle-aged people will realize their ideal is likely to be unattainable.

__________________________________________________________________________

2. Fill in the blank in Paragraph 3 with a proper sentence．（within 10 words）

__________________________________________________________________________

3. How do you understand the sentence that “Happiness is U-shaped”? （within 20 words）

__________________________________________________________________________

4. Is mid-life depression a common Phenomenon in the world? How do you know? （within 15 words）

__________________________________________________________________________

5. Translate the underlined sentence in the last paragraph into Chinese

__________________________________________________________________________

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.
72. 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
73. 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.
74. 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
75. 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 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.

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 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