American cities are similar to other cities around the world: American cities are changing, just as American society is changing. After World War Two, the population of most large American cities decreased; however, the population in many Sun Belt cities increase. Los Angeles and Houston are cities where population shifts (转移) to and from the city reflect the changing values of American society. In the late 1940s and early 1950s, city residents became wealthier. They moved out of their apartments in the city to buy their own homes. They bought houses in the suburbs.
Now things are changing. The children of the people who left the cities in the 1950s are now adults. Many, unlike their parents, want to live in the cities. They continue to move to Sun Belt cities and older ones of the Northeast and Midwest. Many young professionals are moving back into the city. They prefer the city to the suburbs because their jobs are there; or they just enjoy the excitement and possibilities that the city offers.
This population shift is bringing problems as well as benefits. Countless poor people must leave their apartments in the city because the owners want to sell the buildings or make apartments for sale instead of for rent. In the 1950s, many poor people did not have enough money to move to the suburbs; now many of these same people do not have enough money to stay in the cities.
Only a few years ago, people thought that the older American cities were dying. Some city residents now see a bright, new future. Others see only problems and conflicts. One thing is sure: many dying cities are alive again.What does the author think of cities all over the world?
| A．They are alive. | B．They are hopeless. |
| C．They are similar. | D．They are different. |
Why did American city residents want to live in the suburbs after World War Two?
| A．Because older American cities were dying. |
| B．Because they were richer and needed more space. |
| C．Because cities contained the worst parts of society. |
| D．Because they could hardly afford to live in the city. |
According to the 4th paragraph, a great many poor people in American cities .
| A．are faced with housing problems | B．are forced to move to the suburbs |
| C．want to sell their buildings | D．need more money for daily expenses |
We can conclude from the text that .
| A．American cities are changing for the worse |
| B．people have different views on American cities |
| C．many people are now moving from American cities |
| D．the population is decreasing in older American cities |
Suppose we built a robot to explore the planet Mars. We provide the robot with seeing detectors(探测器) to keep it away from danger. It is powered entirely by the sun. Should we program the robot to be equally active at all times? No, the robot would be using up energy at a time when it was not receiving any. So we would probably program it to stop its activity at night and to wake up at dawn the next morning.
According to evolutionary(进化的) theory of sleep, evolution equipped us with a regular pattern of sleeping and waking for the same reason. The theory does not deny that sleep provides some important restorative functions. It merely says that evolution has programmed us to perform those functions at a time when activity would be inefficient and possibly dangerous. However, sleep protects us only from the sort of trouble we might walk into; it does not protect us from trouble that comes looking for us. So we sleep well when we are in a familiar, safe place, but we sleep lightly, if at all, when we fear that bears will nose into the tent.
The evolutionary theory explain the differences in sleep among creatures. Why do cats, for instance, sleep so much, while horses sleep so little? Surely cats do not need five times as much repair and restoration as horses do. But cats can afford to have long periods of inactivity because they spend little time eating and are unlikely to be attacked while they sleep. Horses must spend almost all their waking hours eating, because what they eat is very low in energy value. Moreover, they cannot afford to sleep too long or too deeply, because their survival depends on their ability to run away from attackers. The author uses the example of the robot in space exploration to tell us _______.
| A．the differences between robots and men |
| B．the reason why men need to sleep |
| C．about the need for robots to save power |
| D．about the danger of men working at night |
Evolution has programmed man to sleep at night chiefly to help him ______.
| A．keep up a regular pattern of life |
| B．prevent trouble that comes looking for him |
| C．avoid danger and inefficient labor |
| D．restore his bodily functions |
Which of the following is the main idea of the passage?
| A．Evolution has equipped all creatures with a regular pattern of sleeping and waking. |
| B．The study of sleep is an important art of the evolutionary theory. |
| C．Sleeping patterns must be taken into consideration in the designing of robots. |
| D．The sleeping pattern of a living creature is determined by the food it eats. |
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(遗传学). 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. 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 |
According to the passage, the final mouth shape is formed _______.
| A．before birth | B．as soon as one’s teeth are newly set |
| C．sometime after new teeth are set | D．around 15 years old |
Ray Birdwhistell can tell what area of the United States a person is from by _______.
| A．how much he or she laughs | B．how he or she raises his or her eyebrows |
| C．what he or she likes best | D．the way he or she talks |
This passage might have been taken out of a book dealing with ________.
| A．physics | B．chemistry | C．biology | D．none of the above |
Some spiders hunt on the ground, others build webs to trap their food, but the grass water spider catches its prey by running along the surface of the water.
This special water spider lives on the grassy banks of streams where mosquitoes, damsel flies and other insects come to feed and breed.
Although it is one of the largest spiders in New Zealand, it has an unusual ability. It doesn’t disturb the water as it waits for its meal, and there is barely a ripple(波纹) when it skims(掠过) across the surface at lightning speed to catch its prey.
Grass water spiders deal swiftly with larger insects like damsel flies by pulling their heads under the water and holding them there until they drown.
After a meal, the grass water spider spends up to half an hour grooming(修饰) itself. It wipes its eight eyes, brushes its antennae(触角), and takes special care to clean the hairs on its body.
It is the hairs that trap tiny bubbles(泡沫) of air so that the spider can run down a blade(叶片) of grass and stay underwater for up to an hour when it is frightened. The hairs also keep the spider dry, even underwater.
It is only when the female spider is caring for the young that she does not hunt on the water. After mating, she produces a large egg sac(囊), which she carries around for five weeks. Once the eggs start to hatch, she attaches the sac to some blades of grass or a thistle. She then tears the sac open and releases the tiny spiders into the nursery web.How does the grass water spider kill its prey?
| A．in a web | B．by drowning | C．by poisoning | D．with its antennae |
the writer describes the special spider as “special” because _______.
| A．it walks on water | B．it has eight eyes |
| C．of its hairy appearance | D．of the way it produces its young |
The passage tells us that the spider ______.
| A．feeds grass and thistles to its young. |
| B．lives on blades of grass under the water |
| C．lives in the grass on the banks of streams |
| D．eats a meal once every five weeks |
The purpose of the passage is to _______.
| A．convince readers that spiders are dangerous |
| B．indicate that the grass water spider is endangered |
| C．list all of the spiders that can be found in New Zealand |
| D．describe the characteristics of the grass water spider |
Space travel is definitely bad for astronauts’ bones, reducing their bone density(密度) after only a month of weightlessness, according to French research published on Friday.
Laurence Vico and his fellow workers at St Etienne University called for more research into the effects of microgravity, after their study of 15 astronauts from the Russian MIR station showed bone loss continued throughout space flights.
“Bone loss was especially striking in four astronauts, ” the scientists reported in the Lancet Medical Journal.
They measured the bone mineral density (BMD) of bones in the forearm(前臂) and lower leg of the astronauts who had spent one to six months in space.
The BMD loss was significant in the tibia(胫骨) of the lower leg, a weight-bearing bone, but barely changed in the radius(桡骨) of the forearm. “Our results indicate the need to investigate not only different bones, but also different areas of the same bone since not all sites of the skeleton (骨架) are similarly affected by space conditions, ” they added.
Without gravity the body isn’t bearing any weight so there is no need for calcium (钙) which makes bones strong, and it becomes empty into the bloodstream.
The research team suggested in future scientists should try to determine if the loss of bone density was only on weight-bearing bones on longer flights, also the possible recovery after returning to Earth.French scientists did their research on Russian astronauts, because _______.
| A．they only cared for the Russian astronauts |
| B．they were not interested in their own astronauts |
| C．the Russian government invited them to do their research |
| D．the Russian astronauts worked in space for a long time |
Scientists have found that _______.
| A．the BMD loss may cause serious illness to astronauts |
| B．the BMD loss may cause some change in astronauts’ bodies |
| C．astronauts shouldn’t care about the BMD loss |
| D．astronauts should take some calcium before space travel |
What cause the BMD loss to astronauts, according to this passage?
| A．The food they eat in space. | B．The drinks they take in space. |
| C．The temperature in space. | D．The gravity in space. |
In the third paragraph, the word “striking” means ______.
| A．unusual | B．simple | C．weak | D．slow |
Technology is the application(应用) of knowledge to production. Thanks to modern technology, we have been able to increase greatly the efficiency of our work force. New machines and new methods have helped cut down time and expense while increasing overall output. This has meant more production and a higher standard of living. For most of us in America, modern technology is thought of as the reason why we can have cars and television sets. However, technology has also increased the amount of food available to us, by means of modern farming machinery and animal breeding techniques, and has extended our life span via(通过) medical technology.
Will mankind continue to live longer and have a higher quality of life? In large measure the answer depends on technology and our ability to use it widely. If we keep making progress as we have over the past fifty years, the answer is definitely yes. The advancement of technology depends upon research and development, and the latest statistics(统计) show that the United States is continuing to pump billions of dollars annually(每年) into such efforts. So while we are running out of some scarce resources(少的资源) we may well find technological substitutes(代用品)for many of them through our research programs.
Therefore, in the final analysis the three major factors of production(land, labor and capital) are all influenced by technology. When we need new skills, on techniques in medicine, people will start developing new technology to meet those needs. As equipment proves to be slow or inefficient, new machines will be invented. Technology responds to our needs in helping us maintain our standard of living. What is the best title for the passage?
| A．The definition of technology | B．Modern technology |
| C．The application of technology | D．The development of technology |
Which is the main idea of the passage?
| A．Modern technology is the key to the improvement of standard of living. |
| B．The three major factors of production (land, labor and capital) are all influenced by technology. |
| C．Technology is the response to our needs. |
| D．The United States is making great efforts to advance its technology. |
According to the passage, people can live a long life with the help of _______.
| A．higher quality of life | B．medical technology |
| C．modern farming machinery | D．technological substitute |
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