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1、阅读理解(三)介绍说明A2018朝阳一模 In the days before electricity, people dont worry much about sleep.They usually went to bed a couple of hours after sunset(日落) and woke at sunrise. After all, there wasnt much to do in those days after the sun went down.But then came the electric light bulb(电灯泡).And now we have
2、satellite television, the Internet, 24-hour convenience stores, and longer hours at work.How much can we sleep? How much should we sleep? Like it or not, many of us are sleeping less on average(平均).In 1910, most Americans slept 9 hours a night.That dropped to 7.5 hours by 1975.In 2002, a study by th
3、e National Sleep Foundation found that the average American got only 6.9 hours.The news is even worse for people who work the night shift.They sleep an average of just 5 hours. Are we sleeping enough? Not if you believe in the old rule of eight hours of rest, eight hours of work, and eight hours of
4、play.On the other hand, Norman Stanley, a British scientist who studies sleep, believes peoples sleep needs are different.Some people need as many as 11 hours, but others need as few as three.How much do you really need?“To find out,” he says,“simply sleep until you wake naturally, without the help
5、of an alarm clock.Thats your sleep need.” Meanwhile, other scientists and researchers are searching for new ways to keep us awake longer.Some are developing chemicals(化学药品) that are safer and more powerful than caffeine, the chemical found in coffee and tea.One experimental drug, CX717, kept laborat
6、ory monkeys working happily for 36 hours.Further developments may allow people to safely stay awake for several days straight.One group of researchers is studying a gene(基因) found in some fruit flies that lets them get by on one-third the usual amount of sleep.Another group is even working on an ele
7、ctric switch that immediately wakes up a sleeping brain.The meanings of this research are huge.On the one hand, this could lead to a world where we work longer and longer hours with less and less sleep.On the other hand, if we needed less sleep, we would have more free time to travel, read, voluntee
8、r, and spend time with family.1.How many hours did most Americans sleep a night in 1975?A.5.B.6.9.C.7.5.D.9.2.What can we learn from the passage?A.People have got enough sleep.B.People will work longer hours.C.Sleep time will be a big problem.D.Staying awake for long is possible.3.What is probably t
9、he best title of the passage?A.To Sleep or Not to Sleep? B.How Can We Sleep Longer?C.To Work or Not to Work? D.How Much Can We Sleep?B2018海淀一模 Everyone has traits(特性) that make us who we are.We have physical traits, like red hair, long legs and funny-looking toes.We also have character traits includ
10、ing humor, warmth, creativity and so on.Certain physical traits are fully inherited(遗传), such as blue eyes, and knobby knees.About 25,000 to 35,000 genes(基因) are in a single cell in the human body.These genes carry the traits that are passed down genetically from parents to their children.Many trait
11、s exist between inheritance and developmentthe interaction with environment.One example is body shape.It tends to be passed down from parents.But once diet becomes a factor, environment begins to play an important role in how the body develops.Body shape is a trait that is a mixture of inheritance f
12、rom parents and influence of environment.So lots of our most important traits have been learned, rather than inherited.For example, if you are really great at video games, its not because your parents passed down the skills in genes.Its because you have practiced a lot of video games and developed t
13、hose skills yourself.If you have kids who turn out to be great at video games, it is because they put in the hours, learned the skills, and memorized the moves that are necessary to play the video games well.Of course, some of us have brains that are more advantageous to video game playing.Say you w
14、ere born with a large and powerful part of the brain that controls your hand-eye coordination(协调能力).Thats inherited.What you do with it, how you choose to develop that advantage, is up to you.You can pierce your nose or get a tattooit doesnt matter how much you change your body during the lifetime.N
15、one of those things will turn into genetic material to be passed down to the next generation.However, if your children grow up in an environment with role models who are pierced and covered in tattoos, they are more likely to get piercings and tattoos!1. is a physical trait that is fully inherited.A
16、.The eye color B.The special dietC.The body shape D.The pierced nose 2.According to the passage, the writer believes that .A.character traits can hardly change during the lifetimeB.the skills of video game playing are passed down to kidsC.a kids hand-eye coordination isnt related to inheritanceD.environment plays an important role in trait development 3.Which of the following wou
