Why did humans evolve to walk upright? Perhaps because it’s just plain easier. Make that “energetically less costly”, scientifically speaking.
Bipedalism—walking on two feet, is one of the defining characteristics of being humans, and scientists have debated for years how it came about. In the latest attempt to find an explanation, researchers trained five chimps(黑猩猩)to walk on a treadmill(跑步機(jī))while wearing masks that allowed measurement of their oxygen consumption. The chimps were measured both while walking upright and while moving on their legs and knuckles(膝關(guān)節(jié)).That measurement of the energy needed to move around was compared with similar tests on humans and the results are published in this week’s online edition of “Proceedings of the National Academy of Sciences”.
It turns out that humans walking on two legs use only one-quarter of the energy that chimps use while knucklewalking on four limbs(肢).And the chimps, on average, use as much energy using two legs as they did when they used all four limbs.
However, there were differences among chimps in how much energy they used, and this difference corresponded to their different manner of walking and anatomy(解剖構(gòu)造).One of the chimps used less energy on two legs, one used about the same and the others used more, said David Raichlen, assistant professor of anthropology at the University of Arizona.
“What we were surprised at was the variation(變異) ”, he said in a telephone interview. Interview. “That was pretty exciting, because when you talk about how evolution works, variation is the bottom line, without variation there is no evolution.”
Walking on two legs freed our arms, opening the door to drive the world, said Raichlen. “We think about the evolution of bipedalism as one of first events that led hominids(原始人)down the path to being humans.”
The research was supported by the National Science Foundation and the L.S.B.Leakey Foundation.
小題1: The underlined word “Bipedalism” in Paragraph 2 probably means____.
A．moving sidewaysB．walking upright
C．walking on four legsD．running fast
小題2:We can infer from the passage that____.
A．scientists have no idea on how humans’ walking on two legs came about
B．scientists have had different views on why chimps walk on four legs
C．scientists have had different views on how humans’ walking on two legs vame about
D．scientists have had similar views on how humans’ walking on two legs came about
小題3:What is Paragraph 4 mainly about?
A．How chimps saved energy.
B．Why chimps didn't walk on two legs.
C．David Raichlen studied chimps.
D．Different chimps consumed different energy.
小題4: According to the passage, humans walk upright in order to____.
A．conserve energyB．differ from other animals
C．free their brainsD．strengthen their legs

小題1:B
小題2:C
小題3:D
小題4:A

小題1:破折號(hào)后的內(nèi)容即是對(duì)Bipedalism的解釋，故B項(xiàng)正確。
小題2:由第二段第一句可知。
小題3:第四段主要講了不同的黑猩猩直立行走所消耗的能量是不同的。
小題4:通過全文可知，人類直走的目的是為了減少能量的消耗。
練習(xí)冊(cè)系列答案
相關(guān)習(xí)題

科目：高中英語 來源：不詳 題型：閱讀理解

Every human being has a unique① arrangement of the skin on his fingers and this arrangement is unchangeable. Scientists and experts have proved the uniqueness of finger-prints and discovered that no exactly similar pattern is passed on from parents to children, though nobody knows why this is the case.
The ridge structure on a person’s fingers does not change with growth and is not affected by surface injuries. Burns, cuts and other damage to the outer part of the skin will be replaced in time by new one, which bears a reproduction of the original② pattern. It is only when the inner skin is injured that the arrangement will be destroyed. Some criminals make use of this fact to remove their own finger-prints but this is a dangerous and rare step to take.
Finger-prints can be made very easily with printer’s ink. They can by recorded easily. With special methods, identification③ can be achieved successfully within a short time. Because of the simplicity and economy of this system, finger-prints have often been used as a method of solving criminal case. A suspected man may deny a charge but this may be in vain. His finger-prints can prove who he is even if his appearance has been changed by age or accident.
When a suspect leaves finger-prints behind at the scene of a crime, they are difficult to detect with the naked eye. Special techniques are used to “develop” them. Some of the marks found are incomplete but identification is possible if a print of a quarter of an inch square can be obtained.
Notes:
①    unique  adj. 唯一的，獨(dú)特的
②    original  adj. 最初的，原始的
③    identification  n. 辯認(rèn)，鑒定
小題1: Scientists and experts have proved that the pattern of a human being’s finger skin ________.
A．is similar to his mother’s
B．is valuable to himself only
C．is like that of others with the same type of blood
D．is different from that of all others
小題2: If your fingers are wounded by knife, fire or other means, the structure of skin will ________.
A．be changed partlyB．be replaced by a different one
C．be the same when the wound is recoveredD．become ugly
小題3: Some criminals remove their own finger-prints by ________.
A．using printer’s inkB．injuring the inner skin
C．damaging the outer skin D．damaging the colour
小題4: Finger-prints have often been used as a method of solving criminal case because it ________.
A．is complicated but reliableB．is simple and not expensive
C．is expensive but easy to doD．can bring a lot of money

查看答案和解析>>

科目：高中英語 來源：不詳 題型：閱讀理解

A desert is a beautiful land of silence and space. The sun shines, the wind blows, and time and space seem endless. Nothing is soft. The sand and rocks are hard, and many of the plants even have hard needles instead of leaves.
The size and location(分布) of the world’s deserts are always changing. Over millions of years, as climates change and mountains rise, new dry and wet areas develop. But within the last 100 yeas, deserts have been growing at a frightening speed. This is partly because of natural changes, but the greatest makers are humans.
Humans can make deserts, but humans can also prevent their growth. Algeria Mauritania is planting a similar wall around Nouakchott, the capital. Iran puts a thin covering of petroleum(石油) on sandy areas and plants trees. The oil keeps the water and small trees in the land, and men on motorcycles(摩托車) keep the sheep and goats away. The USSR and India are building long canals to bring water to desert areas.
小題1:In this passage, “needles” refers to _______.
A．small, thin pieces of steel.
B．long, thin pieces of branches.
C．small pointed growth on the stem(莖) of a plant.
D．small, thin pieces of sticks.
小題2:Which of the following is NOT true?
A．The greatest desert makers are humans.
B．There aren’t any living things in the deserts.
C．Deserts have been growing quickly.
D．The size of the deserts is always changing.
小題3:People in some countries are fighting a battle against _______.
A．the growth of desertsB．the disappearance of desert plants
C．natural changesD．congenital climate
小題4:We can guess that Mauritania and Algeria belong to _______.
A．Asian countries 　　　　B．American countries
C．European countiesD．African countries
小題5:Choose the sentence which best gives the main idea of the passage.
A．The deserts of the world are always changing.
B．Man is to take measures to control the growth of the world’s deserts.
C．Deserts are lands of silence and space.
D．Deserts have grown at a fast pace in the past 10 years.

查看答案和解析>>

科目：高中英語 來源：不詳 題型：閱讀理解

As we know, it is very important that a firm should pay attention to the training of its staff as there exist many weak points in its various departments. Staff training must have a purpose, which is defined when a firm considers its training needs, which are in turn based on job descriptions and job specifications(規(guī)范).
A job description should give details of the performance that is required for a particular job, and a job specification should give information about the behaviour, knowledge and skills that are expected of an employee who works in the position. When all of this has been collected, it is possible to make a training specification. This specifies(詳細(xì)說明) that the training department must teach for the successful performance of the job, and also the best methods to use in the training period.
There are many different training methods, and there are advantages and disadvantages in all of them. Successful training performances depend on an understanding of the difference between learning about skills and training in using them. It is frequently said that learning about skills takes place “off the job” in classroom, but training in using these skills takes place “on the job,” by means of such activities as practice in the workshop.
It’s always difficult to evaluate the costs of a training programme. The success of such a programme depends not only on the methods used but also on the quality of the staff who do the training. A company can often check savings in time and cost by examining the work performed by the workers and technicians who have completed a training programme. The evaluation of management training is much more complex than that.
小題1:     The writer mainly wants to tell us_____by the passage.
A． Why firms should pay attention to staff training
B． Staff training must have a purpose
C． Purposes and methods are most important in staff training
D． How to evaluate a training programme
小題2:A training specification specifies_____
A． the training contents and methods
B． the cost and savings of the programme
C． the performance required for a certain job
D． the behaviour, knowledge and skills expected of an employee
小題3:To be successful in training programmes, we must understand the difference between_____
A． the purposes and the methods
B． job description and job specification
C． what is taught and how it is taught
D． learning about skills and training in using them
小題4:The underlined word “evaluate”means_____
A．find out the price ofB．judge the value of
C．deal withD．expect and believe

查看答案和解析>>

科目：高中英語 來源：不詳 題型：閱讀理解

A computer virus is a program or piece of code that is loaded onto your computer without your knowledge and runs against your wishes. All computer viruses are manmade. Here are some virus prevention tips.
Do not open any files attached to an e-mail from an unknown, suspicious or untrustworthy source.
Do not open any files attached to an e-mail unless you know what it is, even if it appears to come from a dear friend or someone you know. Some viruses can replicate（復(fù)制） themselves and spread through e-mail. Better be safe that sorry and confirm that they really sent it .
Do not open any files attached to an e-mail if the subject line is questionable or unexpected. If the need to do so is there always save the file to your hard drive before doing so.
Delete chain e-mails and junk e-mail. Do not forward（轉(zhuǎn)寄） or reply to any of them. These types of e-mail are considered spam（垃圾郵件）, which contains lots of annoying advertisements and useless information.
Do not download any files from strangers.
Be careful when downloading files from the Internet. Ensure that the source is a legitimate（合法的）and reputable one. Verify（證實(shí)）that an anti-virus program checks the files on the download site. If you are uncertain, don’t download the file at all or download the file to a floppy（軟盤）and test it with your own anti-virus software.
Update your anti-virus software regularly. Over 500 viruses are discovered each month, so you’ll want to be protected. These updates should be at least the products virus signature files. You may also need to update the product’s scanning engine as well.
Back up（備份） your files on a regular basis. If a virus destroys your files, at least you can replace them with your backup copy. You should store your backup copy in a separate location from your work files, one that is preferably not on your computer.
小題1:This passage mainly tells us              .
A．What a computer virus is
B．how to use e-mail safely
C．how to use computers safely
D．how to prevent computer viruses
小題2:Which of the following statements about computer virus is TRUE?
A．A computer virus is a kind of worm
B．Not all computer viruses are manmade
C．Computer viruses run according to our wishes
D．A computer virus is a program or piece of code.
小題3: When we use e-mail, we should                .
A．open all the files we receive
B．open any file even if we don’t know what it is
C．not open any files if the subject line is questionable
D．forward or reply to junk e-mail.
小題4:Which of the following statements is NOT true?
A．We’d better not down load any files from strangers.
B．We’d better download files from a legitimate and reputable source.
C．We should update our anti-virus software regularly.
D．We should store our backup copy in the same location as our work files.

查看答案和解析>>

科目：高中英語 來源：不詳 題型：閱讀理解

Everyone becomes a little more forgetful as they get older, but men's minds decline more than women's, according to the results of a worldwide survey.
Certain differences seem to be inherent in male and female brains: Men are better at maintaining and dealing with mental images (useful in mathematical reasoning<推論；說服> and spatial <空間的>skills), while women tend to excel (擅長(zhǎng)) at recalling information from their brain's files (helpful with language skills and remembering the locations of objects).
Many studies have looked for a connection between sex and the amount of mental decline (衰退) people experience as they age, but the results have been mixed.
Some studies found more age-related decline in men than in women, while others saw the opposite or even no relationship at all between sex and mental decline. Those results could be improper because the studies involved older people, and women live longer than men: The men tested are the survivors, "so they're the ones that may not have shown such cognitive（認(rèn)知的；認(rèn)識(shí)的） decline," said study team leader Elizabeth of the University of Warwick in England.
People surveyed completed four tasks that tested sex-related cognitive skills: matching an object to its rotated（旋轉(zhuǎn)的） form, matching lines shown from the same angle, typing as many words in a particular category (范疇) as possible in the given time, e.g.  "object usually colored gray", and recalling the location of objects in a line drawing. The first two were tasks at which men usually excel; the latter are typically dominated(占有主導(dǎo)地位的) by women.
Within each age group studied, men and women performed better in their separate categories on average. And though performance declined with age for both genders（性別）, women showed obviously less decline than men overall（全部地）.
小題1:The underlined word in the second paragraph means_________.
A．naturalB．greatC．obviousD．a(chǎn)bsolute
小題2:According to the passage, which of the following can Not be typed into the same category?
A．cloudB．sheepC．treesD．goose
小題3:Which of the following statements is true according the article?
A．Men do better than women when it comes to learning English.
B．Women stand out at remembering people’s names.
C．Men excel at typing as many words in a particular category as possible in the given time.
D．Women excel at dealing mathematic problems.
小題4: One important factor that affects the correctness of the results is that _________.
A．the old men tested may not have shown such cognitive decline
B．people surveyed are all old
C．people taking part in this test came from all over the worldD．women live longer than men
小題5:The author aims to tell us that __________.
A．women’s minds perform better than men’s
B．men’s minds decline more with age
C．everyone becomes a little more forgetful as they get older
D．a(chǎn) survey on human’s mind decline was done recently

查看答案和解析>>

科目：高中英語 來源：不詳 題型：閱讀理解

In recent years many countries of the world have been faced with the problem of how to make their workers more productive. Some experts claim the answer is to make jobs more varied. But do more various jobs lead to greater productivity? There is evidence to suggest that while variety certainly makes the worker’s life more enjoyable, it does not actually make him work harder. As far as increasing productivity is concerned, then variety is not an important factor.
Other experts feel that giving the worker freedom to do his job in his own way is important, and there is no doubt that this is true. The problem is that this kind of freedom cannot easily be given in the modern factory with its complicated machinery which must be used in a fixed way. Thus while freedom of choice may be important, there is usually very little that can be done to create it.
Another very important consideration is how each worker contributes to the product he is making. In most factories the worker sees only one part of the product. Some car factories are now experimenting with having many small production lines rather than one large one, so that each worker contributes more to the production of the cars on his line. It would seem that not only is degree of the worker contribution an important factor, therefore, but it is also one we can do something about.
To what extent does more money lead to greater productivity? The workers themselves certainly think this is important. But perhaps they want more money only because the work they do is boring. Money just lets them enjoy their spare time more. A similar argument may explain demands for shorter working hours. Perhaps if we succeed in making their jobs more interesting, they will neither want more money, nor will shorter working hours be so important to them.
小題1:Which of the following is the best way to make workers work harder according to the author?
A．Increasing their pay.
B．Giving them more spare time.
C．Making the work itself meaningful.
D．Replacing large production lines with small ones.
小題2:The reason why a worker cannot have freedom in doing the job in his own way is that _______.
A．the machinery is so complex that it should be fixed
B．the production lines are too large in modern factories
C．the bosses can create very little freedom of choices for workers
D．the machines must be operated strictly according to instructions and rules
小題3:For a worker on an assembly line in a car factory, the job is not enjoyable because _______.
A．he can only make a part of a car
B．he does not know what he is doing
C．his life in spare time is more interesting
D．the importance of his job is not clear to him
小題4:In the article, the word “productivity” means _______.
A．the activity of producing something
B．the production volume in a time unit
C．the plan and the method of production
D．both the quantity and quality of a product
小題5:The best title for this passage may be _______.
A．Problems of Modern Workers
B．Making Jobs More Interesting
C．Pushing Workers to Produce More
D．How to Improve Labor Conditions

查看答案和解析>>

科目：高中英語 來源：不詳 題型：閱讀理解

“Seven out of ten people have tried to learn a language at some point in their life and most wish they could speak one more fluently,” a survey found. “And nine out of ten people want their children to learn foreign languages at primary school,” said the poll for the OCR Examing Board (牛津劍橋皇家考試委員會(huì)).Languages are no longer compulsory(義務(wù)的)for pupils aged 14 and over. But the government wants all primary school pupils in England to learn a language by the end of the decade.
A survey of 1000 people was carried out, which is organised by the National Centre of Language .The study suggested people in London were the most likely(78%) to have studied another language, Scots were next at 74%, followed by the northeast of England (71%).In the west of England, more than six in ten have knowledge of another language.
Barrie Hunt from OCR said, “People are often very negative about Britain，s grasp of foreign languages but in reality the number of people who can speak a second language is impressive. The great joke is that many of these people will have no formal qualification to show their family, friends and employers what they can do. Whether they are fluent or just able to hold a short conversation in another language is unknown.”
He said OCR had set a new language scheme called Asset Languages to encourage people of all ages to learn languages in bite-sized amounts and get a qualification.
The scheme also provides assessment for community languages spoken at home, such as Chinese, Urdu and Punjabi.
Isabella Moore from the National Centre of Languages said, “Employers want evidence of good communication skills, confidence and outward-looking attitudes, so a language qualification is an important addition to anyone，s resume.”
小題1:It can be inferred that___________________________ .
A．foreign language study is popular in UK
B．foreign language study is a must for people of all ages
C．it is especially easy for British people to study foreign languages
D．students of over 14 no longer study foreign languages
小題2:Which of the following has the most to have studied a foreign language?
A．People from Scotland.B．People from the northeast of England.
C．People in London.D．People from the west of England.
小題3: Which statement is true according to the text?
A．A language qualification is the only evidence of a high-quality employee.
B．Speaking foreign languages is the most important skill required in employment among all.
C．A language qualification is very difficult to get in UK.
D．Many people in UK don，t have a qualification although they can speak foreign languages.
小題4: What’s the best title for the text?
A．An Interesting SurveyB．UK Loves After All
C．Language Teaching in UKD．Better to Get a Language Qualification

查看答案和解析>>

科目：高中英語 來源：不詳 題型：閱讀理解

Perhaps the most famous theory, the study of body movement, was suggested by Professor Ray Birdwhistell. He believes that physical appearance is often culturally programmed. In other words, we learn our looks—we are not born with them. A baby has generally informed face features. A baby, according to Birdwhistell, learns where to set the eyebrows by looking at those around-family and friends. This helps explain why the people of some areas of the United States look so much alike, new Englanders or Southerners have certain common face features that cannot be explained by genetics(遺傳學(xué)). The exact shape of the mouth is not set at birth, it is learned after. In fact, the final mouth shape is not formed until well after new teeth are set. For many, this can be well into grown-ups. A husband and wife together for a long time often come to look alike. We learn our looks from those around us. This is perhaps why in a single country area where people smile more than those in other areas. In the United States, for example, the South is the part of the country where the people smile most frequently. In New England they smile less, and in the western part of New York State still less. Many southerners find cities such as New York cold and unfriendly, partly because people on Madison Avenue smile less than people on Peachtree Street in Atlanta. Georgia. People in Atlanta, Georgia. People in largely populated areas also smile and greet each other in public less than people in small towns do.
小題1:Ray Birdwhistell believes that physical appearance _______.
A．has little to do with culture
B．has much to do with culture
C．is ever changing
D．is different from place to place
小題2:According to the passage, the final mouth shape is formed _______.
A．before birthB．a(chǎn)s soon as one’s teeth are newly set
C．sometime after new teeth are setD．a(chǎn)round 15 years old
小題3:Ray Birdwhistell can tell what area of the United States a person is from by _______.
A．how much he or she laughsB．how he or she raises his or her eyebrows
C．what he or she likes bestD．the way he or she talks
小題4:This passage might have been taken out of a book dealing with ________.
A．physicsB．chemistryC．biologyD．none of the above

查看答案和解析>>

同步練習(xí)冊(cè)答案