One and a half bananas ____ left on the table.
A.is | B.are | C.has | D.have |
高三英语单项填空简单题
One and a half bananas ____ left on the table.
A.is | B.are | C.has | D.have |
高三英语单项填空简单题查看答案及解析
– What’s left in the bottle standing on the table?
– ________
A.No one | B.None | C.Nobody | D.Nothing |
高三英语单项填空简单题查看答案及解析
– How much wine is left in the bottle standing on the table?
– ________
A.No one | B.None | C.Nobody | D.Nothing |
高三英语单项填空简单题查看答案及解析
How much time did the man probably spend on the exam?
A. Half an hour.
B. 45 minutes.
C. One hour and a half.
高三英语短对话简单题查看答案及解析
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.
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 structured
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.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
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
高三英语阅读理解困难题查看答案及解析
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.
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 structured
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.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
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
高三英语阅读理解中等难度题查看答案及解析
Penguins are flightless birds that spend half their time on land and half in the water.
1. They have dark and white feathers,and their wings have evolved into flippers(脚蹼).Most penguins feed on fish,squid and other forms of sea life caught while swimming.
2. They are mostly found in groups that include thousands of penguins.Penguins each have their own unique mating call,and they use that to locate their mate and chicks in such a large group.
Although almost all penguin species are native to the Southern Hemisphere, they are not found only in cold Antarctica.3. Several species are even found in the temperate zone, and one species,the Galátpagos penguin,lives near the equator(赤道).
Unfortunately, many penguin species worldwide are facing threats.The biggest is climate change and global warming. As the earth warms up,the sheets of ice have melted,and the algae(藻类)that grow under the ice decrease.The algae are eaten by tiny creatures called zooplankton. When there is a drop in zooplankton, it affects the fish that depend on it.4.
Another major threat is from oil spills. If coated with oil, penguins cannot float or swim in water. Also, if oil is swallowed, penguins will die from poison.5.
A.These birds are very social.
B.In fact, only a few of them live so far south.
C.Penguins are highly adapted for life in the water.
D.The biggest threat for penguins comes from humans.
E.They have a tendency to live in a community together.
F.As a result,penguins have less fish to eat and thus starve.
G.Others include overfishing,illegal egg harvesting,and natural enemies.
高三英语七选五中等难度题查看答案及解析
____ of the land in that district ____ covered with trees and grass.
A.One half; are | B.Two seventh; is |
C.A quarter; is | D.Two thirds; are |
高三英语单项填空简单题查看答案及解析
____ of the land in that district ____ covered with trees and grass.
A. One half; are B. Two seventh; is
C. A quarter; is D. Two thirds; are
高三英语单项填空中等难度题查看答案及解析
The local people are now________ Hong Kong, which was once ________the British for one and half a century.
A. in charge of; in charge of B. in the charge of; in the charge of
C. in the charge of; in charge of D. in charge of; in the charge of
高三英语单项填空中等难度题查看答案及解析