题目
题型:不详难度:来源:
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 |
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. |
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 |
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
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。
核心考点
试题【Plants can’t communicate by moving or making sounds, as most animals do. Instead】;主要考察你对题材分类等知识点的理解。[详细]
举一反三
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 |
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 |
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. |
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 |
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 |
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 |
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 |
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 |
A.different from learning other skills |
B.the same as learning skills |
C.more important than other skills |
D.not really important skills |
A.Let Us Teachers Stop Work |
B.Let Us Make Children Learn |
C.Let Children Correct Their Exercises |
D.Let Children Learn by Themselves |
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 |
A.a waste of money | B.a quick repair | C.an easy way out | D.a cheap aid |
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 |
A.the instructions to take Somnapure |
B.the side effects of Somnapure |
C.the price of Somnapure |
D.the way to get Somnapure |
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 book | B.a man | C.a dog | D.a disease |
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. |
A.Squirrels. | B.Ducks. | C.Cats. | D.Bats. |
A.医生 | B.请客 | C.治疗 | D.待遇 |
A.Don’t keep pets | B.How to keep pets |
C.Watch out for rabies | D.Pets with rabies |
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 |
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. |
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 |
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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