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While sleeping, some water mammals 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
答案
更多“While sleeping, some water mammals tend to keep half awake in order to _________.A．alert t”相关的问题
第1题
As it is, sleep is so undervalued that getting by on fewer hours has become a badge of honor. Plus, we live in a culture that_____(36)to the late-nighter, from 24-hour grocery stores to online shopping sites that never close. It's no surprise, then, that more than half of American adults don't get the 7 to 9 hours of shut-eye every night as_____(37)by sleep experts.
Whether or not we can catch up on sleep-on the weekend, say-is a hotly_____(38)topic among sleep researches. The latest evidence suggests that while it isn't_____(39), it might help. When Liu, the UCLA sleep researcher and professor of medicine, brought_____(40)sleep-restricted people into the lab for a weekend of sleep during which they logged about 10 hours per night, they showed_____(41)in the ability of insulin(胰岛素)to process blood sugar. That suggests that catchup sleep may undo some but not all of the damage that sleep_____(42)causes, which is encouraging given how many adults don't get the hours they need each night. Still, Liu isn't_____(43)to endorse the habit of sleeping less and making up for it later.
Sleeping pills, while helpful for some, are not_____(44)an effective remedy either. “A sleeping pill will_____(45)one area of the brain, but there's never going to be a perfect sleeping pill, because you couldn't really replicates(复制)the different chemicals moving in and out of different parts of the brain to go through the different stages of sleep," says Dr.Nancy Collop, director of the Emory University Sleep Center.
A.alternatively
B.caters
C.chronically
D.debated
E.deprivation
F.ideal
G.improvements
H.necessarily
I.negotiated
J.pierce
K.presumption
L.ready
M.recommended
N.surpasses
O.target
第2题
Dreams start when the" inner mind" is opened. This is the place where memories are stored. Often dreams are hard to understand. This is because the inner mind sometimes uses symbols.
Symbols are words or pictures that stand for something else. Most symbols stand for things that have just happened. They can also stand for thing that happened a long time ago. By using symbols, the inner mind can show people things in dream5 that they did not know about themselves. The symbol is another way of showing what really happened.
Dreams have close ties with sleep. People sleep 33 percent of their lives. This is called sleep time. People dream during 25 percent of sleep time.
While they are sleeping, people "tune out" the things around them. But when they dream, people may seem to sense the same things they de when they are awake. They may sometimes see, hear, taste, smell, and feel things in their dreams. These things often seem as real to people when they are asleep as when they are awake.
Even though sleeping people seem to be resting, their bodies are working. Scientists have found that the eyes of sleeping people are moving. They have also found out that their brains are sending out waves.
Why has it been difficult for people to find out more about dreams？
A．Different people have different ideas about dreams.
B．Different dreams have different meanings.
C．People can only have their dreams studied when they are sleeping.
D．People only have dreams when they are sick.
第3题
B.What role it has played in evolution.
C. What circumstances may trigger it.
D.In what way it can be beneficial.
What do we learn about Dr. Yuka Sasaki doing her research？A.She found birds and dolphins remain alert while asleep.
B.She found birds and dolphins sleep in much the same way.
C.She got some idea from previous studies on birds and dolphins
D.She conducted studies on birds’ and dolphins’ sleeping patterns.
What did Dr. Sasaki do when re-running her experiment？A.She analyzed the negative effect of irregular tones on brains.
B.She recorded participants’ adaptation to changed environment.
C.She exposed her participants to two different stimuli.
D.She compared the responses of different participants.
What did Dr. Sasaki find about the participants in her experiment？A.They tended to enjoy certain tones more than others.
B.They tended to perceive irregular beeps as a threat.
C.They felt sleepy when exposed to regular beeps.
D.They differed in their tolerance of irregular tones.
What did Dr. Sasaki do when she first did her experiment？A.She monitored the brain activity of participants sleeping in a new environment.
B.She recruited 35 participants from her Department of Psychological Sciences.
C.She studied the differences between the two sides of participants’ brains.
D.She tested her findings about birds and dolphins on human subjects.
请帮忙给出每个问题的正确答案和分析，谢谢！
第4题
听力原文： Coffee can be considered one of nature's greatest gifts.It gives mental and emotional clarity without harmful side effects,and it contains a wealth of nutrients.Yet,when most people drink coffee,they are not thinking that the beverage is improving their health.In fact,some may even feel a little guilty,since some believe coffee isn't good for you at all.
The truth of the matter is: coffee,like anything else,can cause problems if too much is consumed.In the short-term,too much coffee will cause sleeping problems and hypertension.In the long-term,too much coffee will cause stomach problems as well as teeth staining.
As far as the benefits,moderate consumption of coffee,which means 1 to 4 cups a day,provides your body with a wealth of antioxidants.These substances are responsible for eliminating free radicals.They are the chemical byproducts produced any time your body does something.A small number of them can help serve as a buffer against negative elements,but if they aren't kept in check,they can cause health problems.Antioxidants ensure that this doesn't happen.
Even the caffeine content within coffee can be beneficial toward your health.One way it does this is by cleaning the water of your body's cells,which keeps your weight down while cleaning out impurities.
Why do some people feel guilty when they drink coffee？
A．They are not allowed to drink coffee.
B．They think coffee does no good to them.
C．They think coffee is too expensive.
D．They should not drink coffee when working.
第5题
A．Y
B．N
C．NG
第6题
A．Right
B．Wrong
C．Not mentioned
第7题
What does your brain do while you are sleeping？
A．It improves problem-solving skills and creative thinking.
B．It helps you do your best in school.
C．It helps your brain sort out information from your day.
D．It has a good rest.
第8题
What's Happening While Sleeping？
Sleep is very important to humans. The average person spends 220,000 hours of a lifetime sleeping. Until about thirty years ago, no one knew much about sleep. Then doctors and scientists began doing research in sleep laboratories. They have learned a great deal by studying people as they sleep, but there is still much they don't understand.
Scientists study the body characteristics that change during sleep, such as body temperature, brain waves, blood pressure, breathing, and heartbeat. They also study rapid eye movement (REM). These scientists have learned that there is a kind of sleep with REM and another kind with no rapid eye movement (NREM).
NREM is divided into three stages. In stage one, when you start to go to sleep, you have a pleasant floating feeling. A sudden noise can wake you up. In stage two, you sleep more deeply, and a noise will probably not wake you. In stage three, which you reach in less than thirty minutes, the brain waves are less active and stretched out. Then, within another half hour, you reach REM sleep. This stage might last an hour and a half and is the time when you dream. For the rest of the night, REM and NREM alternate.
Body movement during sleep occurs just before the REM stage. The average person moves about thirty times during sleep each night.
Sleep is a biological need, but your brain never really sleeps. It is never actually blank. The things that were on your mind during the day are still there at night. They appear as dreams, which people have been discussing for centuries. At times people believed that dreams had magical powers or that they could tell the future.
Sometimes dreams are terrifying, but they are usually a collection of scattered, confused thoughts. If you dream about something that is worrying you, you may wake up exhausted, sweating, and with a rapid heartbeat. Dreams have positive effects on our lives. During a dream, the brain may concentrate on a problem and look for different solutions. Also, people who dream during a good night' s sleep are more likely to remember newly learned skills. In other words, you learn better if you dream.
Researchers say that normal people may have four or five REM periods of dreaming a night. The first one may begin only a half hour after falling asleep. Each period of dreaming is a little longer, the last one lasting up to an hour. Dreams also become more intense as the night continues. Nightmares usually occur toward dawn.
People dream in color, but many don' t remember the colors. Certain people can control some of their dreams. They make sure they have a happy ending. Some people get relief from bad dreams by writing them down and then changing the negative stories or thoughts into positive ones on the written paper. Then they study the paper before they go to sleep again.
Many people talk in their sleep, but it is usually just confusing half sentences. They might feel embarrassed when someone tells them they were talking in their sleep, but they probably didn't tell any secrets.
Sleepwalking is most common among children. They usually grow out of it by the time they become adolescents. Children don' t remember that they were walking in their sleep, and they don' t usually wake up if the parent leads them back to bed.
Some people have the habit of grinding their teeth while they sleep. They wake up with a sore jaw or a headache, and they can also damage their teeth. Researchers don' t know why people talk, walk, or grind their teeth while they are asleep.
There are lots of jokes about snoring, but it isn' t really funny. People snore because they have trouble breathing while asleep. Some snorers have a condition called sleep apnea (呼吸暂停). They stop
A．Y
B．N
C．NG
第9题
A．Y
B．N
C．NG
第10题
To limit sleep means our health and daytime potential are significantly reduced. So, good sleep strategies are essential in order to feel energized day after day. There is no strategy which works for everyone, so each person needs to experiment. One important thing is that you shouldn't worry too much if you go a few nights without a lot of sleep. It won't ruin your life. On any given night, one in four people can't sleep properly and everyone suffers from a lack of sleep at some time.
How does one minimize this problem？ It is really quite simple. The first thing you must do is to reduce stress as much as possible. Stress is part of everyday life and, while we can never be entirely without stress, it can be managed. This means taking control of your life and focusing on what is important. One sleeping strategy is to sit in a comfortable position, close your eyes and relax all your muscles, breathing easily through your nose. Continue this for ten to twenty minutes. This should help you reduce stress and sleep better. Or, you can try getting plenty of exercise, because a tired body is likely to sleep better.
According to the article, sleep is important because______.
A．it is a period of complete inactivity for the brain
B．it helps us understand what we have already achieved
C．it makes us more effective when we are awake
D．it helps us to lose weight
