Research suggests that a newly-identified gene known as insomniacs(失眠症患者) may pl

Research suggests that a newly-identified gene known as insomniacs(失眠症患者) may pl

题型:不详难度:来源:
Research suggests that a newly-identified gene known as insomniacs(失眠症患者) may play a role in keeping us asleep. By cloning and testing this gene in about 21,000 fruit flies, Rockefeller University researchers say they have discovered an entirely new mechanism (机制) by which sleep is controlled.
By studying these flies, the researchers discovered that mutations(变异) in the insomniac gene were associated with a great reduction in sleep. While a typical fruit fly slept for an average of 927 minutes a day, the mutant flies slept for just 317. They also slept for shorter periods of time, and slept and woke more frequently.
“The results showed a great loss of both the time that the flies’ sleep lasted and their ability to remain asleep after they slept,” says researcher Nicholas Stavropoulos.
The researchers also examined the link between sleep and lifespan, finding that flies with mutations to the insomniac gene lived only about two-thirds as long as unchanged flies. But when the scientists removed insomniac only in neurons(神经细胞)---allowing it to remain in the rest of the flies’ bodies---this difference disappeared; the resulting animals slept poorly but lived just as long.
“This suggests that reduced sleep can be ‘uncoupled’(分开) from reduced lifespan, supporting the idea that some interruptions of sleep do not affect overall health, at least as far as lifespan is concerned,” Stavropoulos says.
Although flies and humans would appear to have little in common when it comes to lifestyle, scientists say that the mechanisms of sleep and wakefulness are likely to be quite similar.
“Sleep is a fundamental behavior in all animals, and it is poorly understood from a scientific standpoint, says Stavropoulos. This work could prove useful in understanding and treating sleep disorders”
小题1:The text is mainly about____.
A.the progress in cloning fruit flies
B.the methods of cloning fruit flies
C.the link between gene and lifespan
D.the influence of a gene on the ability to sleep
小题2:According to paragraph2, the mutant flies________.
A.slept about 5 hours a day
B.had problems waking up
C.didn’t seem sleepy at all
D.could not fall asleep
小题3:We can conclude from the text that________.
A.sleep and health go hand in hand
B.sleep can be controlled by humans
C.research into sleep is very fruitful
D.the findings are useful in medical treatment

答案

小题1:D
小题2:A
小题3:D
解析

试题分析:本文叙述了通过对果蝇的科学研究发现基因影响睡眠的能力,而一般情况下果蝇睡眠平均每天927分钟,变异果蝇睡了只有317分钟,他们睡眠的时间更短了,睡着了,醒来时却更频繁。苍蝇和人类在生活方式上似乎没有什么共同点,但是睡眠和清醒的情况也可能非常相似。这个研究发现可能对于治疗睡眠障碍有一定的帮助。
小题1:主旨大意题。根据By studying these flies, the researchers discovered that mutations(变异) in the insomniac gene were associated with a great reduction in sleep.可知基因影响睡眠的能力,故选D。
小题2:细节理解题。根据the mutant flies slept for just 317,变异果蝇一天睡眠的时间大约5个小时,故选A。
小题3:推理判断题。根据This work could prove useful in understanding and treating sleep disorders,故选D。
点评:主旨大意题的难度较大,此类题目一般不易直接找到答案,最简单的方法是仔细研究文章开头的一二句,因为他们常是文章的主题句,然后,快速浏览文章首句和结尾句。如果第一句的主题不明,可注意结尾是否有概括总结,对选项要注意全面性和概括性。
举一反三
Almost everyone suffers from a headache sometimes.But some people suffer from repeated, frequent headaches.
What is headache? What causes it? What can be done about a headache? What research is being done on headaches?
The dictionary defines(下定义) headache simply as “a pain in the head.” What most people mean by headache is a pain which lasts several minutes or hours.It covers the whole head, or one side of it, or perhaps the front or the back of the head.To add to the confusion(困惑) about a definition, some people call tight feeling in the head a headache.
A headache is important because it can be the first warning of a serious condition which probably could be controlled if discovered early.If a person removes the warning, day after day, with a pain-killer, he may pass the point of easy control.
The professional name for covering up a symptom(症状) is “masking” (遮蔽).A headache specialist once said, “Masking symptoms is not the best way of treatment.” He compared taking a pain-killer for a headache before a cause is known with taking iron pills for anemia(贫血症) while bleeding continues undiscovered.He added, “Sometimes it is wiser to stand still than to advance in darkness.
A headache is important also because it affects normal, happy living.The employee with a headache does less work.In a flash of temper he may upset his fellow workers or customers, causing a direct or indirect loss to his organization.The mother with a headache suffers and disturbs the family.She upsets her husband and children.
小题1:Which is true according to the passage?
A.Headache has no effect on others.
B.Headache may cover the whole body.
C.Headache may last several minutes or hours.
D.Headache is just the tight feeling in the head.
小题2:The sentence underlined in Paragraph 5 means ______.
A.you should not advance in darkness whatever happens
B.you’d better do nothing before you know how to deal with it
C.you’d better still stand there without moving when it is dark at night
D.you should take some pain-killers for your headache if you want to cover it up
小题3:What may the writer talk about in the following paragraph?
A.Treatments of headachesB.The definition of headaches
C.Symptom of headachesD.Bad effects of a headache
小题4:The passage mainly tells us______.
A.the reason of headache
B.headache and its effect
C.everyone suffers from a headache
D.a headache is a symptom of something serious

题型:不详难度:| 查看答案
Several animal species including gorillas in Rwanda and tigers in Bangladesh could risk extinction if the impact of climate change and extreme weather on their habitats is not addressed, a UN report showed on Sunday.
Launched on the sidelines of global climate negotiations in Durban, the report by the United Nations Food and Agriculture Organization shows how higher temperatures, the rise in sea levels, deforestation and excessive land use have damaged the habitats of certain species, especially in Africa.
“Many ecosystems have already been stressed by increasing population, historical and recent deforestation, unsustainable management practices and even invasive (入侵的) species,” Eduardo Rojas-Briales, assistant director general at the FAO"s forestry department, said at the launch of the report.
The most affected areas include mountains, isolated islands and coastal areas, which limit the possibilities for animals to migrate elsewhere and create new habitats.
“The remaining populations become surrounded in very small ecosystems, they have inbreeding (近亲交配) problems ... and at the end these species may disappear,” he added.
Other examples of affected animals included elephants in Mali, lions in the Serengeti and crocodiles in Malawi.
The report said an estimated 20-30 percent of plant and animal species will be at higher risk of extinction due to global warming and a significant proportion of native species may become extinct by 2050 as a consequence.
Other consequences could include the spread of invasive species and infectious diseases, it said.
The report urges more focus on restoration of damaged ecosystems, especially those key to dealing with climate change such as mangroves(红树林), inland waters, forests, savannahs(非洲大草原) and grasslands.
The FAO also called for the creation of migration corridors for animals in areas where their movement was limited.
The organization said while more resources were flowing to biodiversity conservation, more action at the government and policy level was needed.
It also urged local communities to develop projects that mitigate the impact of climate change on wildlife, naming eco-tourism activities as an example.
小题1:What does the author tell us in Paragraph 2?
A.The theme of global climate negotiations in Durban.
B.The subject of research done by Eduardo Rojas.
C.Causes of damage done to ecosystems.
D.Harmful effects of damage done to ecosystems.
小题2:Why are animals living in mountains, islands and coastal areas most affected?
A.They are frequently attacked by invasive species and infectious diseases.
B.They have difficulty finding enough food for survival.
C.They can hardly find mates to produce their young.
D.They have little chance of moving to other places.
小题3:To avoid extinction of some animal species, the UNFAO suggested all the following ways EXCEPT ______.
A.restoring damaged ecosystems
B.limiting world population growth
C.creating movement channels for animals
D.urging governments and local communities to take action
小题4:What does the underlined word “mitigate” in the last paragraph mean?
A.increase or further improve something.
B.Make full use of something.
C.Make something become less serious.
D.Move from one place to another.
小题5:What would serve as the best title for the passage?
A.Animals at risk due to climate change.
B.Global warming and its consequences.
C.Climate change and ecotourism.
D.Solutions to animal distinction.

题型:不详难度:| 查看答案
China_is_going_green. In order to reduce air pollution and oil­shortages, automobile manufacturers have announced their plans to develop hybrid vehicles (混合燃料汽车) for the Chinese market. Toyota"s hybrid car Prius will be ready to drive in China this week. Let"s have a look at the new car.
Any vehicle is a hybrid when it combines two or more sources of power. Hybrid cars run off a rechargeable battery and gasoline. Hybrid cars have special engines, which are smaller than traditional gasoline engines. They run at 99 percent of their power when the car is cruising (匀速行驶). A specially designed battery motor provides extra power for running up hills or when extra acceleration is needed.
Step into a Prius, and turn on the engine. The first thing you notice is how much quieter it is than a traditional car. At this point, the car"s gasoline engine is dormant (休眠). The electric motor will provide power until the car reaches about 24 km/h. If you stay at a low speed, you are effectively driving an electric car, with no gasoline being used, and no waste gas gives off.
The onboard(车载的) computer makes the decision about when to use a gas engine, when to go electric, and when to use a combination of the two. If you go over 24 km/h, when you step on the gas pedal (油门), you are actually telling the computer how fast you want to go.
The electronic motor recharges automatically using a set of batteries. When driving at high speed, the gasoline engine not only powers the car, but also charges the batteries. Any time you use the brake, the electric motor in the wheels will work like a generator and produce electricity to recharge the batteries. As a consequence, the car"s batteries will last for around 200,000 miles.
小题1:The author writes this passage mainly to________.
A.teach people how to drive a hybrid car
B.introduce a new kind of “green” car
C.show how to save their gasoline when driving a car
D.announce plans to develop hybrid vehicles for China
小题2:The first sentence probably refers to ________.
A.there will be more and more green land in China
B.China is still young and lacking experience
C.China"s new cars are combinations of different green models
D.China has started producing environmentally friendly cars
小题3:Which of the followings is NOT true?
A.The hybrid cars reduce air pollution and oil­shortages.
B.The car"s gasoline engine doesn"t work until it reaches about 24 km/h.
C.This kind of car is completely controlled by an onboard computer.
D.A specially designed battery motor provides extra power when needed.
小题4:What is the most important feature of hybrid cars?
A.They are powered by both a rechargeable battery and gasoline.
B.They are much quieter than traditional cars.
C.They only use 99 percent of their power to run up hills.
D.They have smaller engines than traditional gasoline ones.

题型:不详难度:| 查看答案
The fourth round of heavy smog to hit Beijing in four weeks has sent more people to the hospital with respiratory(呼吸的) illnesses and led to calls for laws to control the pollution.
Pan Shiyi, a celebrity real estate developer said he is planning to propose (提案) a Clean Air Act to the local government. As a representative to the Beijing Municipal People"s Congress, he started an online survey at 9:20 a.m. Within three hours, more than 25,000 web users, or 99 percent of total respondents(应答者), welcomed his proposal on Sina Weibo, China"s Twitter.
They have good reasons to stand alongside Pan. The latest round of haze(雾霾)reduced visibility to under 500 meters in many parts of the city. The smog has also led to a great increase in respiratory illnesses, particularly among children and the elderly. Anxious parents and doctors almost all blame the smoggy air for the illnesses. Though most schoolchildren are home for the winter holidays, the bad air can easily move indoors. Besides, ordinary medical masks fail to provide adequate protection, so some people have turned to gas masks and respirators(呼吸器).
The causes of the scary smog are rather mysterious, though experts blame excessive emissions and the mountains around Beijing that trap pollution in winter, unless there is adequate wind to clear it away. Some critics have pointed fingers at China’s top two oil firms, China National Petroleum Corp and China Petrochemical Corporation, saying the companies’ outdated production technologies produce large quantities of substandard, high-polluting gas fuel.
Meanwhile, concerned Beijingers have moved their brainstorming sessions to cyberspace. If Pan’s proposal for a Clean Air Act is adopted, netizens say the new law should include items providing for “car-free days” in times of smog, higher standards for vehicle fuel, stricter restrictions on industrial and exhaust gas emissions, and more effective protection for the public.
Beijing is not the only city that has ever lost the blue sky. Five days of thick fog caused thousands of deaths in Britain in December 1952, urging the government to pass the first Clean Air Act in 1956, which introduced smokeless zones and cleaner fuels to reduce pollution. That may provide some experience for Beijing to refer to.
小题1:What can we learn from the passage?
A.People are clear about the causes of the smoggy weather.
B.Children staying indoors will not get respiratory illnesses.
C.Smog is worse for people with lower resistance to diseases.
D.Masks can give people protection against the smoggy weather.
小题2:Britain is mentioned in the last paragraph to ______.
A.suggest Beijing should learn from other countries
B.let people know many places have this problem
C.tell people the situation in Britain is worse
D.call on the government to pass Britain’s Clean Air Act
小题3:What’s the best title for this passage?
A.The Use of Gas masks and Respirators
B.Beijingers Call for Clean Air Act
C.Effective Protection for Blue Sky
D.The Mysterious Causes of the Scary Smog

题型:不详难度:| 查看答案
My son loves video games very much. He spends hours every day playing video games in his room. Is there any redeeming(补偿的)educational value to video games? Some seem like they could help him learn strategy. But I worry others may be too violent or numb(使麻木)his mind.
Cecilia
Some games may improve kids’ hand-eye coordination and problem-solving skills. Games that require kids to actually move or manipulate(操纵)the game through their own physical movement can even get sedentary kids moving, though not as much as they could if they actually played outside or participated in sports or other outdoor acuities. Others, though, don’t have such benefits, and violent video games have been shown that they might increase kid’s aggressive behavior.
Like a lot of aspects of raising kids, when it comes to video games, the healthiest approach is actually self-control.
The American academy of Pediatrics(AAP) recommends that kids should spend no more than 2 hours each day on screen time, including watching TV or movies, or playing computer or video games. So consider setting limits at least that strict to keep game playing from affecting their schoolwork, household responsibilities, and the physical activity your son needs very day.
Make sure that he’s playing games which are suitable for his age group. All video games are rated and labeled by the Entertainment Software Rating Board. Steer clear of(避开)any rated “M” for mature. Those are for ages 17 and older and can contain heavy-duty violence, strong language, and sexual content.
Try to keep the video game console(游戏机控制板)in a common area of the house, not your son’s room. That way you can catch any inappropriate content in the games he’s playing, and he’ll be in a position to interact with others in the house while he’s playing.
Make sure your son has appealing alternatives, too, such as sports, activities, opportunities to socialize with peers; and downtime to be creative. If you continue to have concerns about his video game activity, talk with your doctor.
Reviewed by:Mary L. Gavin, MD
小题1:What is the opinion of Mary L. Gavin about playing video games?
A.Whether it’s beneficial or harmful depends on what the video games are.
B.It always improves kids’ hand-eye coordination and problem-solving skills.
C.It will make kids more violent and increase their aggressive behavior.
D.Kids should give it up and put their hearts fully into their schoolwork.
小题2:The underlined word “sedentary” in the first paragraph of the answer letter is the nearest in meaning to “______”.
A.unhealthyB.livelyC.brightD.inactive
小题3:According to Mary L. Gavin, which of the following is encouraged to do by parents?
A.Keep the video game console out of their house.
B.Allow their children to play only such video games as rated “M”
C.Let kids play video games as much as possible if it doesn’t affect their lessons.
D.Help their children develop other healthy hobbies such as sports and painting.
小题4:Which is the best title of this passage?
A.Should children play video games?
B.Kids’ playing video games is harmful.
C.Is playing video games good for kids?
D.Help children choose video games.

题型:不详难度:| 查看答案
最新试题
热门考点

超级试练试题库

© 2017-2019 超级试练试题库,All Rights Reserved.