Plants can’t communicate by moving or making sounds, as most animals do. Instead

Plants can’t communicate by moving or making sounds, as most animals do. Instead

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Plants can’t communicate by moving or making sounds, as most animals do. Instead, plants produce volatile compounds (挥发性化合物) —— chemicals that easily change from a liquid to a gas. A flower’s sweet smell, for example, comes from such volatile compounds to attract insects such as bugs and bees.
Plants can also discover  volatile compounds produced by other plants. A tree under attack by hungry insets, for instance, may give off these chemicals in order to let other trees know about the attack. In response, the other trees may send off their chemicals to keep the bugs away —— or even chemicals that will attract the bugs’ natural enemies.
Now scientists have created a quick way to understand what plants are saying: a chemical sensor (传感器) called an “electronic nose”. The “e-nose” can tell such compounds as plants make. When plants are attacked, scientists say, the e-nose could help quickly decide whether plants are being eaten by insects. But today, the only way to spot such insects is to inspect individual plants by observing them. This is a challenging task for managers of greenhouses, including those that can house thousands of plants. The research team is working with an e-nose that can recognize volatile compounds. Inside the device, 13 sensors chemically react with volatile compounds based on the interactions (相互作用), and then the e-nose will give off electronic signals that the scientists can analyze by using computer software.
To test the e-nose, the team presented it with healthy leaves from cucumber, pepper and tomato plants, all being common greenhouse crops. Then scientists collected samples of the air around damaged leaves from each type of crop. These plants had been damaged either by insects or by scientists who made holes in the leaves with a hole punch (打孔器).
The e-nose, it turns out, can identify healthy cucumber, pepper and tomato plants based on the volatile compounds they produce. It could also identify tomato leaves that had been damaged. But even more impressive, the device could tell which type of damage —— by insects or with a hole punch —— had been done to the tomato leaves.
With some fine-tuning (微调), a device like the e-nose can one day be used in greenhouses to quickly spot harmful bugs, the researchers say. A device like this can also be used to identify fruits that are perfectly ripe and ready to pick and eat, says Natalia Dudareva, a biochemist at Purdue University in West Lafayette, India, who studies smells of flowers and plants. Hopefully, scientists believe, the device can bring large benefits to greenhouse managers in the near future.
小题1:We learn from the text that plants communicate with each other by ______.
A.making some sounds
B.waving their leaves
C.producing some chemicals
D.sending out electronic signals
小题2:What did the scientists do to find out if the e-nose worked?
A.They fixed 13 sensors inside the device.
B.They presented it with all common crops.
C.They collected different damaged leaves.
D.They do tests on damaged and healthy leaves.
小题3:According to the writer, the most amazing thing about the e-nose is that it can ______.
A.pick out ripe fruits quite expertly
B.spot the insects in a very quick way
C.tell different damages to leaves
D.recognize unhealthy tomato leaves
小题4:We can infer from the last paragraph that the e-nose ______.
A.is unable to tell the smell of flowers
B.is not yet tested in greenhouses
C.is designed by scientists at Purdue
D.is helpful in killing harmful insects

答案

小题1:C
小题2:D
小题3:C
小题4:B
解析
植物会说话吗?植物如何"交流"?本文中的科学家们正在尝试用e-nose来测试植物受到伤害时的反应。
小题1:细节理解题。从文章第一段中的"Instead,plants produce volatile compounds,chemicals that..."可知,植物通过它本身所产生的一种化学物质来进行交流,所以答案选C。
小题2:推理判断题。从文章第五段可知,为了证实e-nose的效果,科学家用受到伤害的叶子与健康的叶子来测试。所以选D。
小题3:细节理解题。从倒数第二段中的"But even more impressive,the device could tell which type of damage..."可知,最令人惊奇的是e-nose能够分辨叶子受到的不同的"伤害"。
小题4:推理判断题。从文章最后一段中的"could one day be used in greenhouses to..."推断可知,e-nose还没有运用到greenhouses中,由此推断B是答案。
举一反三
Due to the increasing number of violence acts produced in schools all over the world,more and more parents prefer to have their children educated at home rather than at school. This way they can assure their safety and well-being,although teachers and school representatives are trying to improve the situation in schools by increasing the number of the persons in charge with the safety of the students.
The main reason for violence acts are the films and cartoons that fill the children’s time.They want to do everything.they watch on TV and never think at the consequences,and they may hurt a classmate or a teacher.
On the other hand, parents are not fully satisfied with the children’s results obtained in classes and they consider private classes would have better results.
When a teacher has to watch 30 students in class he can’t probably see what each of them is doing,how he is writing,or if he understands the explanations.At home the teacher can explain in details everything the child doesn’t understand as many times as he considers proper.
And many times.the child grows fond of the teacher at home,who becomes his best friend,and who helps him whenever he needs someone to talk to.    
However, the best solution would be a mixture between the education received at school and that at home,because school makes children communicate and socialize.Keeping a child at home for fear there might happen something bad to him.only makes the child’s character weak and prevents him from knowing what real life is.Staying in a crystal ball only does harm to the child.
All in all.schools have been created to help children,not to harm them,so it’s best to keep children in these special places,where they learn,laugh,have fun and make new friends.
小题1:The writer’s purpose in writing the text is to          
A.teach parents the ways to keep theft children safe
B.show solutions to developing children’s character
C.explain the main reason for violence acts in schools
D.analyze an education problem and give opinions
小题2:Parents prefer to have their children educated at home because the following EXCEPT that______.
A.More and more violence acts occur in schools
B.Parents want to improve their Children"s grades
C.Parents are concerned about their children’s safety
D.The education system is far from satisfactory
小题3:What does“a crystal ball”in the passage refer to?
A.A toy that can be used for entertainment.
B.A safe and comfortable environment.
C.An object that is made of crystal.
D.A setback that is hard to overcome.
小题4:We call infer from the passage that          
A.violence TV programs have bad effects on children’s behavior
B.The teacher at home is more patient than the teacher at school
C.Children today are weak from lack of sense of right and wrong
D.There are too many students in class for a teacher to teach
小题5:Which of the following might be the best title of the passage?
A.Advantages and Disadvantages of Private Classes
B.Who is to Blame, Parents or Schools?
C.Which is Better, School Study or Home Study
D.The Relationship between Teachers and Children

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Let children learn to judge their own work. A child learning to talk does not learn by being corrected all the time; if corrected too much, he will stop talking. He notices a thousand times a day the difference between the language he uses and the language those around him use. Bit by bit, he makes the necessary changes to make his language like other people’s. In the same way, children learn to do all the other things without being taught to walk, run, climb, whistle, ride a bicycle…They compare their own performances with those of more skilled people, and slowly make the needed changes. But in school we never give a child a chance to find out his mistakes and correct them for himself. We do it all for him. We act as if we thought that he would never notice a mistake. If it is a matter in mathematics or science, give him the answer book. Let him correct his own papers. Why should we teachers waste time in such routine(日常的) work? Our job should be to help the child when he tells us that he can’t find the way to get the right answer. Let the children learn what all educated persons must some day learn, how to measure their own understanding, how to know what he does not know.
小题1:According to the passage, the best way for children to learn things is by_____.
A.listening to skilled people’s advice.
B.asking older people many questions
C.making mistakes and having them corrected
D.doing what other people do
小题2:Which of the following does the writer think teachers should NOT do?.
A.Give children correct answers
B.Allow children to mark mistakes.
C.Point out children’s mistakes to them.
D.Let children mark their own work
小题3:According to the writer, teachers in school should _____
A.allow children to learn from each other
B.point out children’s mistakes whenever found
C.correct children’s mistakes as soon as possible
D.give children more book knowledge
小题4:The passage suggests that learning to speak and learning to ride a bicycle are____
A.different from learning other skills
B.the same as learning skills
C.more important than other skills
D.not really important skills
小题5:The title of this passage could probably be_____
A.Let Us Teachers Stop Work
B.Let Us Make Children Learn
C.Let Children Correct Their Exercises
D.Let Children Learn by Themselves

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Does this sound familiar? It’s 3:00 am and you’re still awake and staring at the clock. You can’t sleep , and you’ve already tried all the familiar tricks – taken a warm bath , drunk a glass of heated milk ,tried counting sheep, and read a book –all with no success. If you are such a sufferer, remember you’re not alone. Experts said that one in every four Americans have trouble falling or staying asleep.
Lack of sleep can hurt your quality of life in so many ways. Short temper, impatience, poor decision-making, and mood swings are common among those with sleeping problems. Besides, relationships with family, friends, and co-workers may suffer as a result. Improper sleep can also put your safety at risk by reducing your awareness.
When you’re awake in the middle of the night, you can start to feel desperate for a way out . However, it makes sense to weigh the available treatments before choosing the one that’s right for you. Other sleep aids may seem like a quick fix, but it turns out that there are many disadvantages of these drugs. For one thing, they may require expensive, time-consuming trips to your physician. They may also be habit-forming or have unpleasant side effects like dizziness( 眩晕) dry mouth, and next-day sleepiness. Plus , they become less effective over time.
So what is the best sleep aid available on the market today? The answer is Somnapure , a product that represents nature and science coming together. This all-natural sleep aid which comes from Peak Life allows you to fall asleep quickly and remain asleep through the night . With Somnapure, you wake up feeling refreshed and energetic. Somnapure is currently giving away a 14-day trial here. Get your Somnapure trial for better, deeper sleep that you deserve.
小题1:From paragraph 1, we can know that sleep problems are_______.
A.easy to make a sufferer lonely
B.common but hard to deal with
C.severe throughout the world
D.widespread only in the USA
小题2:The underlined words“ a quick fix”(in paragraph3)most probably means____.
A.a waste of moneyB.a quick repairC.an easy way outD.a cheap aid
小题3:The purpose of the passage is to _______.
A.ask people with sleep problems to try and use Somnapure
B.introduce a kind of medicine to help sleep better
C.draw people’s attention to the bad effects of the lack of sleep
D.talk about what the main causes of the sleep problems are
小题4:We can infer that the passage is probably immediately followed by information about ______.
A.the instructions to take Somnapure
B.the side effects of Somnapure
C.the price of Somnapure
D.the way to get Somnapure

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Do you often play with your pet dog or cat? Do you like touching wild animals such as squirrels? They are cute. But be careful. If they bite you, you may get a terrible disease——rabies.
Believe it or not, in the last five months, rabies killed more people in China than any other disease. 2,254 people got rabies in the first nine months of this year. In September, 318 people died of rabies. That is 37 per cent more than last September.
Animals like dogs, cats, squirrels and bats can have rabies. If they bite or scratch(抓)someone, rabies could infect(感染)the person’s nervous system(神经系统). The person could even die. It’s important to get the right treatment as soon as possible.
Every year, more than 50,000 people around the world die of rabies. Most of them are from developing countries. India has the most deaths. China is second.
小题1:Rabies is the name of _____.
A.a bookB.a manC.a dogD.a disease
小题2:Paragraphs two and three _____.
A.teach people how to deal with rabies.
B.explain the situation in China.
C.order people not to keep pets.
D.show what rabies is really like.
小题3:Which of the following animals might NOT have rabies?
A.Squirrels.B.Ducks.C.Cats.D.Bats.
小题4:The Chinese for the underlined word “treatment” probably is _____.
A.医生B.请客C.治疗D.待遇
小题5:What the best title for the passage?
A.Don’t keep petsB.How to keep pets
C.Watch out for rabiesD.Pets with rabies

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Birds that are half-asleep — with one brain hemisphere (半球) alert(警觉) and the other sleeping — control which side of the brain remains awake, according to a new study of sleeping ducks.
Earlier studies have recorded 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 (打盹) 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 inner 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 developed over time 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.
小题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 organized
D.they have to constantly keep an eye on their companions
小题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.
小题3:It can be inferred that _______.
A.Birds never sleep with both hemispheres resting at once.
B.Inner ducks depend on single-hemisphere sleep, rather than total relaxation, as often as birds napping at the end of the line do
C.It is not the first time for scientists to research on birds’ half-brain sleep
D.Birds hardly sleep without a companion
小题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

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