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（注视）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（发展）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（浮现）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

Imagine when you are sailing an ocean for the first time, you see a big fish swimming near your ship. You might be scared, and worried about whether it will turn over your ship for a meal. In fact, it is not a fish at all, but a gentle giant whale.

Whales are not fishes but mammals (哺乳动物). Their body temperature stays the same, and does not change with the temperature of their environment. They breathe air, so they have to come out of the water to get oxygen. Thus, they cannot afford to fall into a sleeping state for too long, since they need to be awake in order to breathe. It is thought that only half of their brains sleep at a time, so that whales are never completely asleep. Females give birth to the young. They have hair. Although they are not covered in hair or fur like many mammals, whales have some bristles (胡子), usually on their heads.

Whales are highly social animals with complex languages and intelligence. They communicate with each other using romantic sounds, called “whale songs”. Being so large and powerful, these sounds are also loud.

Whales are endangered as a result of whaling (捕鲸) from the eleventh century to the twentieth. It has attracted the attention of environmentalists and some measures (措施) have been taken to protect whales.

1.How many aspects show that whales are mammals?

A．One.             B．Two.              C．Three.            D．Four.

2.We can infer from the second paragraph that ____.

A．whales can breathe in the water

B．if a whale sleeps too long, it will get drowned

C．in order to breathe, whales never sleep

D．whales give birth to the young on the land

3. How do whales communicate with each other?

A．By body language.                       B．By speaking languages.

C．By making song-like sounds.               D．By giving off a smell.

4.Which of the following is TRUE according to the passage?

A．Whales are cold-blooded mammals like fishes.

B．Whales are hunted for food by people.

C．Whales are very harmful to human beings.

D．Whales are in danger because of being killed by people.

III.完型填空（共15小题；每小题1分，满分15分）
I stayed at home with my 5-year-old daughter Lily. When I was reading some magazines, Lily played in the living room. But after a while I noticed nothing but  31     .           
She had never been so quiet. Was she   32   ? I asked what she was doing. The   33    finally came after I   34   my question three times. I heard “Nothing”. Never could I believe she just stayed there and kept quiet. So I walked into the living room. She hurried off. I   35    her to turn around but she   36  . I got a little angry. “Young lady,” I said, “turn around!”
37   she turned toward me. In her hand was my wife’s new lipstick, only a little   38  . Besides her lips, every inch of her face was covered with bright red.
As she looked up at me with   39   eyes, I really got angry. I was about to   40   at her so that she would know what a mistake she had made.  41   before I could shout, I noticed the big letters she had written on her white skirt with the lipstick, “I’M  A  PERFECT  ANGEL!”
Something strange   42  me. I looked back at her red face. This time, instead of seeing a  43  girl, I saw a little angel that I had almost missed!
“Lily, I heard you speak to the toys just now. I guess you were teaching them how to use the lipstick. But should an angel use her mom’s lipstick like this?” Lily lowered her head, “Sorry. I won’t do it again.” I smiled. “Go and wash your face and let’s get a new  44  for mom.”
Every child is an angel. I felt   45  that I didn’t hurt the angel through treating her mistake in a right way.
31. A. sound          B. laughter       C. silence        D. music
32. A. sleeping        B. laughing       C. running       D. standing
33. A. news           B. result         C. report         D. reply
34. A. read            B. wrote         C. found         D. repeated
35. A. allowed         B. advised       C. ordered        D. persuaded
36. A. accepted        B. forgot         C. refused        D. understood
37. A. Suddenly        B. Slowly       C. Happily        D. Sadly
38. A. left             B. gone        C. lost           D. saved
39. A. excited          B. frightened     C. surprised       D. disappointed
40. A. shout            B. beat         C. drive          D. hold
41. A. But             B. So           C. And          D. Or
42. A. pulled          B. left          C. pushed         D. hit
43. A. foolish          B. bad           C. clever         D. boring
44. A. skirt            B. lipstick        C. present        D. magazine
45. A. sad             B. interesting      C. fortunate      D. sorry

A Swedish man was dug out alive after being snowed in his car on a forest track for two months with no food, police and local media reported on Saturday.
The 45-year-old from southern Sweden was found on Friday, February17, too weak to say more than a few words.
He was found not far from the city of Umea in the north of Sweden by snowmobilers who thought they had come across a ruined car until they dug their way to a window and saw movement inside.
The man, who was lying in the back seat in a sleeping bag, said he had been in the car since December 19.
“Just incredible that he’s alive considering that he had no food, but also since it’s been really cold for some time after Christmas.” a rescue team member told regional daily Vasterbottens- Kuriren, which broke the news.
Ebbe Nyberg, duty officer at the Umea police, said police saw no reason to doubt that the man had been stuck in the car for a very long time.
“We would not make up something like this. The rescue services were on site too and saw the same as us.” he told Vasterbottens-Kuriren.
Umea University Hospital, where the man is recovering after being rescued by police and a rescue team, said in a statement he was doing well considering the circumstances.
Doctors at the hospital said humans would normally be able to survive for about four weeks without food. Besides eating snow, the man probably survived by going into a dormant-like(休眠似的) state, physician Stefan Branth told Vasterbottens-Kuriren.
“A bit like a bear that hibernates. Humans can do that.” he said. “He probably had a body temperature of around 31 degrees which the body adjusted to. Due to the low temperature, not much energy was used up.”
“Why the man ended up under the snow in the forest remains unknown,” police said.
【小题1】Who found the Swedish man in the snow?

A Swedish man was dug out alive after being snowed in his car on a forest track for two months with no food, police and local media reported on Saturday.
The 45-year-old from southern Sweden was found on Friday, February17, too weak to say more than a few words.
He was found not far from the city of Umea in the north of Sweden by snowmobilers who thought they had come across a ruined car until they dug their way to a window and saw movement inside.
The man, who was lying in the back seat in a sleeping bag, said he had been in the car since December 19.
“Just incredible that he’s alive considering that he had no food, but also since it’s been really cold for some time after Christmas.” a rescue team member told regional daily Vasterbottens- Kuriren, which broke the news.
Ebbe Nyberg, duty officer at the Umea police, said police saw no reason to doubt that the man had been stuck in the car for a very long time.
“We would not make up something like this. The rescue services were on site too and saw the same as us.” he told Vasterbottens-Kuriren.
Umea University Hospital, where the man is recovering after being rescued by police and a rescue team, said in a statement he was doing well considering the circumstances.
Doctors at the hospital said humans would normally be able to survive for about four weeks without food. Besides eating snow, the man probably survived by going into a dormant-like(休眠似的）state, physician Stefan Branth told Vasterbottens-Kuriren.
“A bit like a bear that hibernates. Humans can do that.” he said. “He probably had a body temperature of around 31 degrees which the body adjusted to. Due to the low temperature, not much energy was used up.”
“Why the man ended up under the snow in the forest remains unknown,” police said.
【小题1】Who found the Swedish man in the snow?