March 21 has been declared World Sleep Day, a time to recognize and celebrate the value of sleep. Many sleep experts hope it will be a wake-up call.
According to a poll (民意调查）by the National Sleep Foundation, nearly 4 in 5 Americans don’t get as much sleep as they should during the workweek. On average, adults are thought to need at least eight hours of sleep a night, although some can manage with less and some won’t do well without more. But the survey found that, on workdays, only 21% of Americans actually get a full eight hours of sleep, and another 21% get less than six.
To many of us, the thought of spending more time sleeping is, well, a big yawn. On the other hand, the thought of being smarter, thinner, healthier and more cheerful has a certain appeal. And those are just a few of the advantages that can be ours if we consistently get enough sleep, researchers say. Also on the plus side: We’re likely to have better skin, better memories, better judgment, and, oh, yes, longer lives.
“When you lose even one hour of sleep for any reason, it influences your performance the next day,” says Dr. Alon Avidan, director of the UCLA Sleep Disorders Center.
A study published last year found the same to be true even of children. When kids aged 8 to 12 slept for just one hour less for four nights, they didn’t function as well during the day.
But sleeping has an image problem. “We see napping or sleeping as lazy,” says Jennifer Vriend, a clinical psychologist in Ottawa, Canada, and the leading author of the study with children. “We put so much emphasis on diet, nutrition and exercise. Sleep is in the back seat.” In fact, she adds, no matter how much we work out, no matter how well we eat, we can’t be in top physical shape unless we also get plenty of sleep.
The underlined part in Paragraph 1 means _____.
| A．To wake up the sleepers |
| B．To draw people’s attention |
| C．To serve as a morning call |
| D．To declare the special day |
From Paragraph 3 we can infer that _______
| A．Being healthier is one of the advantages for us |
| B．Sleeping has nothing to do with one’s expectations |
| C．Spending more time on sleeping is a waste of time |
| D．Enough sleep is the guarantee of the appealing things |
What Jennifer Vriend said in the last paragraph implies that _______.
| A．Sleeping is an image problem |
| B．People care little about sleeping |
| C．Lazy people tend to sleep long |
| D．Sleeping is only part of our life |
What is the purpose of the passage?
| A．To talk about people’s sleeping problems. |
| B．To provide an investigation result of sleeping. |
| C．To arouse the awareness of enough sleeping. |
| D．To stress the function of sleeping at night. |
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 |
Weather changes when the temperature and the amount of water in the atmosphere change. We can see and feel water coming from the atmosphere when we have rain. But the water must somehow get back to the atmosphere. Meteorologists call this the water cycle.
There are many stages in the water cycle. Rain falls when water vapour in clouds condenses(凝结). Drops of water form and fall to the ground. The water soaks into the ground and feeds streams and rivers. A lot of rain falls into the sea. The heat of the sun evaporates some of the water in the ground and in the rivers, lakes, and the sea. It changes the liquid water into water vapour. The vapour rises onto the air. Water vapour is normally invisible. On a very damp or humid day, however, you can sometimes see water vapour rising from a puddle(水坑) or pond in a mist(薄雾) above the water. Water vapour also gets into the air from living things. Trees and other plants take in water through their roots and give off water vapour from their leaves. People and land animals drink water and breathe out water vapour. In all these ways the water returns to the air. There it gathers to form clouds and condenses to form rain. The rain falls to earth, and the cycle starts again. It continues even if snow or hail(冰雹) fall instead because both eventually melt to form water. The amount of water vapour in the air depends on the temperature. The air is more moist(潮湿) in the tropics(热带) than in the cold polar regions. What is the main idea of the passage?
| A．Water cycle. | B．Water vapour. |
| C．How rain forms. | D．Water, vapour, rain. |
How many ways of the water returning to the air are discussed in the text?
| A．Two. | B．Three. | C．Four. | D．Five. |
Whether water vapour can be seen or not depends on _______.
| A．how much water is evaporated | B．how good your eyes are |
| C．in which way water is evaporated | D．climate or weather |
From the passage we get to know _______.
| A．there is more water vapour in the air in the tropics than in cold polar regions |
| B．there is more water vapour in the air in cold polar region than in the tropics |
| C．it gets more rain in the tropics than in cold polar regions because there is less vapour |
| D．the amount of water vapour in the air depends on how often it rains |
Scientists are uncovering the secrets of two port cities lost under the waters of the Mediterranean Sea, a researcher said yesterday.
Herakleion and Menouthis were rich and proud cities until something reduced them to rubble (碎石) and buried them in the mud beneath 30 feet of sea water, French underwater explorer Franck Goddio said at the American Geophysical Union conference.
“This is a mystery that is ongoing,” said Goddio, a founder of the European Institute of Marine Archeology, a Paris-based underwater research organization backed by the wealthy Hilti Foundation of Liechtenstein(列支敦士登基金会).
The destruction of the twin port cities has haunted Goddio ever since he happened upon the site about 15 miles from Alexandria while exploring sunken ships from Napoleon’s fleet.
Goddio and his group of expert divers, marine archeologists(海洋考古学家) and others, are using high powered vacuums, satellite navigation systems and sophisticated sonar(声纳) to excavate(挖掘) the sunken cities from underneath a carpet of silt about one meter (three feet) high.
Walls of shops, remains of streets and gold artifacts have been found and recovered.
Some experts believe that the port cities were destroyed by a series of massive earthquakes, much like the quakes scientists believe felled Troy(特洛伊城), Jericho and other ancient cities. The uniform direction of the collapsed columns and walls suggest an earthquake, Goddio said, but no fault lines have been found nearby.
Other researchers believe a massive wave, caused by either an offshore earthquake or a distant underwater landslide, could explain the catastrophe. Still others think rising seas and a shift in the Nile River outlet doomed the cities.
“The argument, as you can see, continues,” Goddio said.The reason why the two port cities disappeared under the waters of Mediterranean Sea is that ______.
| A．the two port cities were destroyed by huge earthquakes |
| B．the disappearance of the two port cities was caused by underwater landslide |
| C．rising seas and a shift in the Nile River outlet doomed the cities |
| D．the story didn’t tell us at all |
From the story we can draw a conclusion that _______.
| A．the two port cities were famous for their wealth and the mystery |
| B．the two cities belonged to France |
| C．some mysterious creatures from other planets destroyed the two cities |
| D．the American Geophysical Union conference was once held in one of the two cities |
This article is probably from _______.
| A．a scientific magazine |
| B．a report to the government |
| C．a school text book |
| D．a scientific report in a newspaper |
Motherhood may make women smarter and may help prevent dementia(痴呆) in old age by bathing the brain in protective hormones(荷尔蒙) , U.S. reseachers reported on Thursday.
Tests on rats show that those who raise two or more litters of pups do considerably better in tests of memory and skills than rats who have no babies, and their brains show changes that suggest they may be protected against diseases such as Alzheimer’s(早老痴呆症). University of Richmond psychology professor Craig Kinsley believes his findings will translate into humans.
“Our research shows that the hormones of pregnancy(怀孕) are protecting the brain, including estrogen(雌激素), which we know has many neuroprotective (保护神经的) effects,” Kinsley said.
“It’s rat data but humans are mammals just like these animals are mammals,” he added in a telephone interview. “They go through pregnancy and hormonal changes.”
Kinsley said he hoped public health officials and researchers will look to see if having had children protects a woman from Alzheimer’s and other forms of age-related brain decline.
“When people think about pregnancy, they think about what happens to babies and the mother from the neck down,” said Kinsley, who presented his findings to the annual meeting of the Society of Neuroscience in Orlando, Florida.
“They do not realize that hormones are washing on the brain. If you look at female animals who have never gone through pregnancy, they act differently toward young. But if she goes through pregnancy, she will sacrifice her life for her infant—that is a great change in her behavior that showed in genetic alterations(改变) to the brain.” How do scientists know “Motherhood may make women smarter”?
| A．Some researchers have told them. |
| B．Many women say so. |
| C．They know it by experimenting on rats. |
| D．They know it through their own experience. |
What does the phrase “litters of pups” mean in the second paragraph?
| A．Baby rats. | B．Animals. | C．Old rats. | D．Grown-up rats. |
What can protect the brain of a woman according to the passage?
| A．Estrogen. | B．The hormones of pregnancy. |
| C．More exercise. | D．Taking care of children. |
“It’s rat data but humans are mammals just like these animals are mammals.” What does the sentence suggest?
| A．The experiments on the rats have nothing to do with humans. |
| B．The experiments on the rats are very important for animals. |
| C．The experiments on the rats are much the same on humans. |
| D．The experiments on the rats are much the same on other animals. |
Which title is the best for this passage?
| A．Do You Want to Be Smarter? |
| B．Motherhood Makes Women Smarter |
| C．Mysterious Hormones |
| D．An Important Study |