The relationship between exercise and cancer has long both intrigued and puzzled oncologists and exercise physiologists.
Exercise is strongly associated with lowered risks for many types of cancer. At the same time, exercise involves biological stress, which typically leads to a short-term increase in inflammation(发炎) which can contribute to higher risks for many cancers.
Now, a new study in mice may offer some clues into the exercise-cancer paradox. It suggests that exercise may change how the immune system deals with cancer by boosting adrenaline（肾上腺素）, certain immune cells and other chemicals that, together, can reduce the severity of cancer or fight it off altogether.
To try to better understand how exercise can both elevate inflammation and simultaneously protect the body against cancer, scientists at the University of Copenhagen in Denmark and other institutions decided to closely examine what happens inside mice at high risk for the disease.
So, for the new study, they began by gathering a group of adult lab mice. These animals generally like to run.
The scientists then implanted melanoma (黑素瘤) skin cancer cells into the mice before providing half of them with running wheels in their cages while the other animals remained sedentary. After four weeks, far fewer of the runners had developed full-blown melanoma than the sedentary mice and those that had been diagnosed with the disease showed fewer and smaller lesions.
They drew blood from both the exercising and sedentary animals and cells from any tumors in both groups. As expected, they found much higher levels of the hormone adrenaline in the blood of the exercising animals, especially right after they had been working out on the wheels but also at other times of the day. The body releases adrenaline in response to almost any type of stressful experience, including exercise.
They also found higher levels of interleukin-6 in the blood of the runners. This is a substance that is released by working muscles and is believed to both increase and decrease inflammation in the body, depending on where and how it goes to work.
Perhaps most important, they found much higher numbers in the bloodstreams of runners than in the sedentary mice of a type of immune cell named natural killer cells that are known to be strong cancer fighters.
So the scientists repeated their original experiment multiple times, inducing cancer while allowing some mice to run and others to sit. In some of these follow-up experiments, the scientists injected the runners with a substance that blocked the production of adrenaline and gave sedentary animals large doses of added adrenaline.
What they now found was that when running mice could not produce adrenaline, they developed cancer at the same rate as the sedentary animals, while the sedentary animals that had been injected with extra adrenaline fought off their tumors better than other sitting mice.
More remarkably, the scientists determined that adrenaline seemed to be sending biochemical signals to some of the animals’ IL-6 cells, making them physiologically more alert, so that when a tumor began to develop in the affected animal, those IL-6 cells in turn activated the natural killer cells in the bloodstream and actually directed them to the tumors, like minute guide fish.
With these results, “we show that voluntary wheel running in mice can reduce the growth of tumors, and we have identified an exercise-dependent mobilization of natural killer cells as the underlying cause of this protection,” said Pernille Hojman, a researcher at the University of Copenhagen who oversaw the new study. It perhaps provides one more incentive for us to get up and move.
1.In the first experiment, which one is the most important result the scientists found?
A. Natural killer cells are much more in the bloodstreams of runners than in the sedentary mice.
B. Levels of interleukin-6 are higher in the blood of the runners than in the sedentary mice.
C. Exercise such as running seemed to help the mice fight against the cancer.
D. Adrenaline can reduce the severity of cancer or fight it off.
2.In the follow-up experiments, the scientists found ________.
A. the hormone adrenaline has much higher levels in the blood of the exercising animals
B. how these elements in the runners — their increased adrenaline, IL-6, and natural killer immune cells fight against tumor
C. interleukin-6 can both increase and decrease inflammation in the body, depending on where and how it goes to work
D. what happens inside mice at high risk for the disease
3.According to the study, we can infer the fundamental substance to fight the cancer off is ________.
A. adrenalineB. interleukin-6
C. natural killer cellsD. genes
A new argument has been put forward as to whether penguins are disturbed by the presence of tourists in Antarctica.
Previous research by scientists from Keil University in Germany monitored Adelie penguins and noted that the birds’ heart rates increased dramatically at the sight of a human as far as 30 meters away. But new research using an artificial egg, which is equipped to measure heart rates, disputes this. Scientists from the Scott Polar Research Institute at Cambridge say that a slow moving human who does not approach the nest too closely, is not viewed as a threat by penguins.
The earlier findings have been used to partly explain the 20 per cent drop in populations of certain types of penguins near tourist sites. However, tour operators have continued to insist that their activities do not adversely affect wildlife in Antarctica, saying they encourage non-disruptive behavior in tourists, and that the decline in penguin numbers is caused by other factors.
Amanda Nimon of the Scott Polar Research Institute spent three southern hemisphere summers at Cuverville Island in Antarctica studying penguin behavior towards humans. “A nesting penguin will react very differently to a person rapidly and closely approaching the nest,” says Nimon. “First they exhibit large and prolonged(延长) heart rate changes and then they often flee the nest leaving it open for predators (掠夺者) to fly in and remove eggs or chicks.” The artificial egg, specially for the project, monitored both the parent who had been ‘disturbed’ when the egg was placed in the nest and the other parent as they both took it in turns to guard the nest.
However, Boris Culik, who monitored the Adelie penguins, believes that Nimon’s findings do not invalidate his own research. He points out that species behave differently — and Nimon’s work was with Gentoo penguins. Nimon and her colleagues believe that Culik’s research was methodologically flawed（使无效） because the monitoring of penguins’ responses needed capturing and restraining（控制） the birds and fitting them with heart-rate transmitters. Therefore, argues Nimon, it would not be surprising if they became stressed on seeing a human subsequently.
1.According to the passage, what overall message is presented?
A. No firm conclusions are drawn.
B. Neither Culik’s nor Nimon’s findings are of much value.
C. Penguin reduction is closed related to tourist behavior.
D. Tourists are not responsible for the fall in penguin numbers.
2.Which ONE argument of the following is stated in the passage?
A. Penguins are harder to research when they have young.
B. Tour operators should encourage tourists to avoid Antarctica.
C. Not all penguins behave in the same way.
D. Penguins need better protection from tourists.
3.What do you notice about the views presented in the passage?
A. They are groundless.B. They are factual.
C. They are descriptive.D. They are conflicting.
4.What does the underlined word (final line) probably mean?
A. later onB. calmly
C. separatelyD. in the same place
India now leads the world in smartphone growth. It saw a 55% increase in the number of smartphones in 2014. The number of Web users increased by 37%. Smartphones were the source of 65 % of its Internet traffic and 41 % of its e-commerce, according to a report by the analyst Mary Meeker, titled “Internet Trends 2015”.
India’s Internet boom has started. Within three or four years, almost every adult in India will own a smartphone. They will be used to order goods, read news, monitor crop growth and so on.
Indian adults will be very interested in these devices just as young Americans are. 87% of Americans between the ages of 18 and 34 who own smartphones say they never separate from these: “My smartphone never leaves my side.” Four out of five say that the first thing they do on waking is to reach for their smartphones. And three fifths believe that in the next five years everything will be done on mobile devices.
In the business world, the rise of mobile platforms is dramatically transforming many industries all over the world. What Indian software developers have to do is to start thinking about solutions to old problems by using all the features of these new devices. They need to take advantage of the unique properties of smartphones and tablets. As Indian software developers and enterprises master the smartphone, they will be able to export their solutions to the rest of the world.
This will make possible a new tech revolution that is greater than what created India’s IT industry in the 1980s and 1990s. We can expect the rapid transformation of India when a billion people become connected and have equal access to information and services.
1.Loads of numbers are used in Paragraph 1 to show _____________.
A. India’s smartphones increase most rapidly in the world
B. India has the most advanced IT industry in the world
C. India will be a superpower pretty soon
D. India will export new smartphones to the rest of the world
2.What will most young Americans do first the moment they wake up?
A. Read news.B. Shop online.
C. Get their smartphones.D. Check e-mails.
3.Which of the following is TRUE according to the passage?
A. India is the largest mobile maker in the world.
B. Indian farmers will probably use smartphones to monitor crop growth.
C. Indian software developers have made great profits by selling their products abroad.
D. India saw a great boom in IT industry some 30 years ago.
4.Which can be the best title of the text?
A. More people，more smartphones
B. No dream, every Indian owns a smartphone
C. At hand, India’s next tech revolution
D. A small smartphone, a big use
Two thieves came to a house to steal something. They dug a hole in the wall of the house. There lived many mice in the house. The woman in the moonlight saw a mouse crawl into the house.“Look！In comes one，”she said to the man in the house. The thief was so frightened that he hurriedly crawled out of the house and said to the one waiting outside，“She found me when I was just in.” But the thief outside didn’t believe him，so he said，“Let us two try to crawl into the house together.”At that time two mice happened to crawl into the house，too. The woman saw the mice and shouted，“In come two，catch them！” The two thieves were terribly frightened. The man in the house said，“You saw them come in but where are they？ I will catch them tonight.”The two thieves started running away at once.
The two thieves wanted to make it clear whether they had been found or not the night before. The next day they acted as men selling sweet potatoes and came before the house. The man and the woman were ploughing in their fields.
The rein（缰绳）broke and the woman came home for a rope. She saw two men selling sweet potatoes and wanted to buy some. She picked out two which looked like mice. At the time the man couldn’t wait for her any longer in the fields and he ran back from the fields to hurry her up. The woman showed the sweet potatoes to the man and said，“How they look like the two of last night.”The man said，“I asked you to fetch a rope，why don’t you hurry for it？”The two thieves ran away quickly without their sweet potatoes.
1.The two thieves failed to steal anything from the house because ________.
A．they were found out
B．they were frightened by what they had heard in the house
C．they didn’t work together well with each other
D．mice stopped them from doing so
2.From the last paragraph, we know that ________.
A．the two thieves were famous selling sweet potatoes
B．the woman recognized the two thieves
C．the woman pretended to know nothing about the two thieves and made fun of them
D．the two thieves didn’t know that they were not found at all
3.“________”is the best title for this passage.
A．Two Clever ThievesB．Terrible Mice
C．Hit the Mark by a FlukeD．A Clever Couple
4.Which of the following statements is FALSE?
A．The two thieves not only failed to steal things but also lost their sweet potatoes.
B．Whenever they found mice，the people in the house would try to catch them.
C．The two thieves ran away at once，because they thought the woman had seen them.
D．The man let the woman go home for a rope，which would be used for catching the thieves.
认真阅读下面短文，从短文后各题所给的四个选项（A、B、C、D）中，选出可以填入空白处的最佳选项，并在答题卡上将该项涂黑。
Few Americans stay in one place for a lifetime. We ________ from the city to the suburbs, from high school to college in a different state, from a job in one region to a better job ________, from the home where we ________ our children to the home where we plan to live in ________. With each move we are ________ making new friends, who become part of our new life.
For many of us the ________ is a special time for forming new friendships. Today, millions of Americans go on vocation ________, and they go not only to see new sights but also — in those places where they do not feel too ________— with the hope of meeting new people. No one really ________ a vacation trip to produce a close friend, but the beginning of a friendship is possible. Surely in every country people ________ friendship.
The word “friend” to American people can be ________ to a wide range of relationships — to someone one has known for a few weeks in a new place, to a close business companion, to a childhood playmate, to a man or woman, to a ________ colleague. There are real ________ among these relations for Americans — a friendship may be ________, casual, situational or deep and lasting. But to a European, who sees only our surface behavior, the differences are not clear.
As Europeans see it, all kinds of “friends” flow ________ of Americans' homes with little ceremony. They may be parents of the children's friends, house guests of neighbors, members of a committee, business associates from another town or even another country. ________ as a guest into an American home, the European visitor finds no ________ differences. The atmosphere is ________. Most people, old and young, are called ________ first names. Americans’ characteristic openness to different styles of relationship makes it possible for us to find new friends abroad with whom we feel ________.
1.A. driveB. commuteC. moveD. settle
2.A. abroadB. elsewhereC. somewhereD. nowhere
3.A. deliverB. protectC. educateD. raise
4.A. retirementB. deathC. illnessD. sadness
5.A. mostlyB. mainlyC. rarelyD. forever
6.A. winterB. summerC. springD. autumn
7.A. alongB. freelyC. togetherD. abroad
8.A. aloneB. strangeC. scaredD. remote
9.A. allowsB. desiresC. expectsD. imagines
10.A. formB. developC. ignoreD. value
11.A. usedB. appliedC. stuckD. dedicated
12.A. kindB. generousC. trustedD. helpful
13.A. differencesB. varieties
C. distinctionsD. diversities
14.A. informalB. reliableC. shallowD. fragile
15.A. in and outB. on and onC. by and byD. up and down
16.A. MovingB. FlowingC. GoingD. Coming
17.A. obviousB. heavyC. explicitD. strong
18.A. weirdB. stressedC. relaxedD. strange
19.A. withB. onC. forD. by
20.A. at bestB. at homeC. at heartD. at hand
—I’ve nothing on me except this ten yuan to donate, I’m afraid.
—Never mind. ________. We really appreciate your assistance.
A. Every little helps
B. The more, the better
C. It’s better to give than to receive
D. No one is perfect
