The most important factor in Google’s ...

单项选择题One thing that distinguishes the online world from the real one is that it is very easy to find things. To find a copy of The Economist in print, one has to go to a news-stand, which may or may not carry it. Finding it online, though, is a different proposition. Just go to Google, type in "economist" and you will be instantly directed to economist.com. Though it is difficult to remember now, this was not always the case. Indeed, until Google, now the world’s most popular search engine, came on to the scene in September 1998, it was not the case at all. As in the physical world, searching online was a hit-or-miss affair.
Google was vastly better than anything that had come before: so much better, in fact, that it changed the way many people use the web. Almost overnight, it made the web far more useful, particularly for non- specialist users, many of whom now regard Google as the internet’s front door. The recent fuss over Google’s stock market flotation obscures its far wider social significance: few technologies, after all, are so influential that their names become used as verbs.
Google began in 1998 as an academic research project by Sergey Brin and Lawrence Page, who were then graduate students at Stanford University in Palo Alto, California. It was not the first search engine, of course. Existing search engines were able to scan or "crawl" a large portion of the web, build an index, and then find pages that matched particular words. But they were less good at presenting those pages, which might number in the hundreds of thousands, in a useful way.
Mr Brin’s and Mr Page’s accomplishment was to devise a way to sort the results by determining which pages were likely to be most relevant. They did so using a mathematical recipe, or algorithm, called PageRank. This algorithm is at the heart of Google’s success, distinguishing it from all previous search engines and accounting for its apparently magical ability to find the most useful web pages.
Untangling the web
PageRank works by analysing the structure of the web itself. Each of its billions of pages can link to other pages, and can also, in turn, be linked to. Mr Brin and Mr Page reasoned that if a page was linked to many other pages, it was likely to be important. Furthermore, if the pages that linked to a page were important, then that page was even. more likely to be important. There is, of course, an inherent circularity to this formula—the importance of one page depends on the importance of pages that link to it, the importance of which depends in turn on the importance of pages that link to them. But using some mathematical tricks, this circularity can be resolved, and each page can be given a score that reflects its importance.
The simplest way to calculate the score for each page is to perform a repeating or "iterative" calculation I see article). To start with, all pages are given the same score. Then each link from one page to another is counted as a "vote" for the destination page. Each page’s score is recalculated by adding up the contribution from each incoming link, which is simply the score of the linking page divided by the number of outgoing links on that page. (Each page’s score is thus shared out among the pages it links to.)
Once all the scores have been recalculated, the process is repeated using the new scores, until the scores settle down and stop changing (in mathematical jargon, the calculation "converges". The final scores can then be used to rank search results: pages that match a particular set of search terms are displayed in order of. descending score, so that the page deemed most important appears at the top of the list.
The most important factor in Google’s success is ______.

A．its unique mathematical recipe
B．the popularity of its brand among users
C．that it was the first search engine in the world
D．its stock market flotation

点击查看答案&解析

你可能感兴趣的试题

1.问答题Love is the most wonderful thing in the world. People always hope to own the perfect love. Here comes the question: Do you believe there is such a thing called "’The Perfect Love" You are asked to write a composition of about 400 words on the following topic:
Does the perfect love exist
In the first part of your writing you should present your thesis statement, and in the second part you should support the thesis statement with appropriate details. In the last part you should bring what you have Written to a natural conclusion with a summary.
Marks will be awarded for content, organization, grammar and appropriateness. Failure to follow the above instructions may result in a loss of marks.

参考答案：Does the Perfect Love Exist
Most of u...

点击查看完整答案

2.单项选择题From the conversation we know if we buy more products from the Universal Computers Ltd., ______.

A．we can earn more mone
B．we can benefit more
C．they will give us more service
D．they will move their main building to China

点击查看答案

3.单项选择题Fish farming in the desert may at first sound like an anomaly, but in Israel over the last decade a scientific hunch has turned into a bustling business.
Scientists here say they realized they were no to something when they found that brackish water drilled from underground desert aquifers (含土水层) hundreds of feet deep could be used to raise warm-water fish. The geothermal water, less than one-tenth as saline as sea water, free of pollutants and a toasty 98 degrees on average, proved an ideal match.
"It was not simple to convince people that growing fish in the desert makes sense," said Samuel Appelbaum, a professor and fish biologist at the Jacob Blaustein Institutes for Desert Research at the Sede Boqer campus of Ben-Gurion University of the Negev.
"It is important to stop with the reputation that arid land is nonfertile, useless land," said Professor Appelbaum, who pioneered the concept of desert aquaculture in Israel in the late 1980s. "We should consider arid land where subsurface water exists as land that has great opportunities, especially in food production because of the low level of competition on the land itself and because it gives opportunities to its inhabitants."
The next step in this country, where water is scarce and expensive, was to show farmers that they could later use the water in which the fish are raised to irrigate their crops in a system called double usage. The organic waste produced by the cultured fish makes the water especially useful, because it acts as fertilizer for the crops.
Fields watered by brackish water dot Israel’s Negev and Arava Deserts in the south of the country, where they spread out like green blankets against a landscape of sand dunes and rocky outcrops. At Kibbutz Mashabbe Sade in the Negev, the recycled water from the fish ponds is used to irrigate acres of olive and jojoba groves. Elsewhere it is also used for irrigating date palms and alfalfa.
The chain of multiple users for the water is potentially a model that can be copied, especially in arid third world countries where farmers struggle to produce crops, and Israeli scientists have recently been peddling their ideas abroad.
Dry lands cover about 40 percent of the planet, and the people who live on them are often among the poorest in the world. Scientists are working to share the desert aquaculture technology they fine-turned here with Tanzania, India, Australia and China, among others. (Similar methods offish farming are being used in the Sonoran Desert of Arizona.)
"Each farm could run itself, which is important in the developing world," said Alon Tal, a leading Israeli environmental activist who recently organized a conference on desertification, with the United Nations Convention to Combat Desertification and Ben-Gurion University, that brought policy makers and scientists from 30 countries to Israel.
"A whole village could adopt such a system," Dr. Tal added.
At the conference, Gregoire de Kalbermatten, deputy secretary general of the antidesertification group at the United Nations, said, "We need to learn from the resilience of Israel in developing dry lands."
Israel, long heralded for its agricultural success in the desert through innovative technologies like drip irrigation, has found ways to use low-quality water and what is considered terrible soil to grow produce like sweet cherry tomatoes, people, asparagus and melon, marketing much of it abroad to Europe, especially during winter.
The history of fish-farming in nondesert areas here, mostly in the Galilee region near the sea, dates back to the late 1920s, before Israel was established as a state. At the time, the country was extremely poor and meat was considered a luxury. But fish was a cheap food source, so fish farms were set up on several kibbutzim in the Galilee.
The early Jewish farmers were mostly Eastern Europeans, and Professor Safriel said, "they only knew gefilte fish, so they grew carp."
Eventually they expanded to other varieties of fish including tilapia, striped bass and mullet, as well as ornamental fish.
The past decade has seen the establishment of about 15 fish farms producing both edible and ornamental fish in the Negev and Arava Deserts.
Fish farming, meanwhile, has became more lucrative worldwide as people seek more fish in their diet for better health, and ocean fisheries increasingly are being depleted.
The practice is not without critics, who say it can harm the environment and the fish. In Israel there was a decision by the government to stop fish fanning in the Red Sea near the southern city of Eilat by 2008 because it was deemed damaging to nearby coral reefs.
Some also argue that the industry is not sustainable in the long term because most of the fish that are fanned are carnivorous and must be fed a protein-rich diet of other fish, usually caught in the wild. Another criticism is that large numbers of fish are kept in relatively small areas, leading to a higher risk of disease.
Professor Appelbaum said the controversy surrounding fish farming in ocean areas does not apply to desert aquaculture, which is in an isolated, controlled area, with much less competition for resources.
According to Professor Appelbaum, what is the important step to convince people it is possible to develop fish farming in desert

A．To inform them fish farming is a lucrative industry worldwide as people seek more fish in their diet for better health.
B．To rid them of the preconception that arid land is unfertile and useless.
C．To help them with technical support.
D．To persuade government to provide more economic support.

点击查看答案&解析

4.问答题相识的人并不就是朋友。我们和许多人相识，或是因了事务关系，或是因了偶然的机缘——如在别人请客的时候同席吃过饭之类。见面时点头或握手，有事时走访或通信，口头上彼此也称“朋友”，笔头上有时或称“仁兄”，诸如此类，其实只是一种社交上的客套，和“顿首”、“百拜”同是仪式的虚伪。这种交际可以说是社交，和真正的友谊相差似乎很远。

参考答案：Not all acquaintances are friends. We come to know many peop...

点击查看完整答案&解析

5.填空题Contrast to researchers’ expectations, dysfunctional family relationships and poor (1)______
communication styles appear to have much effect on whether young children become (2)______
depressed, a study has found. While many children under 5 exhibit symptoms of
depression, they often have not been exposed against known risk factors, experts find. (3)______
And many children who are exposed to those risk factors~ appear to be resilient.
In the study, Australian researchers looked at many factors, including marital partner (4)______
change, mothers’ health in pregnancy, a child’s health in the first six months of life and
marital anxiety in more than 5,000 mothers over a period of five years. But few of them
correlated to early childhood depression. The authors warned that their results, published (5)______
in the June issue of Social Psychiatry and Psychiatric Epidemiology, depended on reports
by mothers about their children’s experience, and that the mothers’ emotional states might (6)______
have affected those reports. They also conceded that young, lonely, low-income mothers (7)______
were often lost as to follow-up during the years of the study, and that the children of (8)______
those mothers might be expected to have higher rate of depression. "If what we have (9)______
found is correct," said Dr. Jake Najman, the lead author and a professor of sociology
at the University of Queensland, "then depression in children has a large constitutional
component" that is transmitted either genetically or by exposure to risks before or during
pregnancy. Dr. Najman suggested that early invention might help prevent depression (10)______
from developing in early life.

参考答案：against→to。

6.单项选择题1)People with diabetes have too much sugar in their blood, so a drug that lowers blood sugar ought to be a good treatment, right
2) Maybe not. Consider the diabetes drug Avandia, or rosiglitazone, which was approved in 1999．it lowers blood sugar, and about a million people in the United States have been talking it for Type 2 diabetes, the most common form of the disease. But last week, doctors reported that Avandia might increase the risk of heart attacks.
3) Heart disease is a major complication of diabetes, so a drug that could make the risk even worse is bad news indeed.
4) The jury is still out on Avandia. Meanwhile, patient advocates and some politicians and researchers are already denouncing it, and the Food and Drug Administration has issued a tepid "safety alert" telling patients to ask their doctors what to do while the agency "is carefully weighing several complex sources of data." Avandia’s manufacturer, GlaxoSmithKline, insists it is safe. Personal injury lawyers are advertising on the Internet for clients who think they were injured by the drug.
5) What happened here reflects a larger question—the tricky problem of how to judge whether a drug is safe and effective. Avandia was approved because it lowered blood sugar, and seemed safe in clinical trials.
6) But the real test of whether a drug is any good is how are the patients Not their blood tests or X-rays or EKGs, but the people themselves, and not after just six months, but after years, especially if they have a chronic disease and will be talking medicine for the rest of their lives. Are those talking the drug more or less likely than people not talking it to have heart attacks, die or develop heart disease or other illnesses
7) The problem is, it can take a long time and a lot of patients—and, therefore, a lot of money — to get a real picture of health and survival. That is especially true for something like heart disease, which develops slowly and is so common that it may be hard to detect a small increase in risk. Studies might have to go on for years instead of months, and include far more than the few thousand patients in whom drugs are typically tested before they get approved.
8) So instead of waiting to see if people die or have heart attacks, drug companies have looked for other traits that seem to correlate with health and survival and that could stand in as a yardstick—objective measures like blood pressure, cholesterol (胆固醇) levels, blood sugar or tests of heart function. Researchers call these measurements "surrogate endpoints," and the F. D．A．has encouraged companies to find surrogates that could reliably predict how patients would fare. These kinds of tests are seen as a way to streamline the drug approval process.
9) But reliable surrogates are hard to find. There are plenty of endpoints that in theory should do the job, but do not. Tumor size, for instance: there are drugs that Can shrink tumors without prolonging a patient’s life. Bone density is another example. Fluoride can increase it in people whose skeletons have thinned from osteoporosis (骨质疏松症) , so fluoride should prevent fractures. But it doesn’t, in fact, it makes fractures more likely, because it turns bones brittle.
10) Heart rhythm can also be deceptive. Certain medicines can stabilize dangerous, abnormal heartbeats in people who have had heart attacks—and yet have been found to increase their odds of dying. Cholesterol levels do not always tell the whole story, either. Hormone treatment in women after menopause (绝经期) can raise HDL (高密度脂蛋白) , the so-called good cholesterol, and so was expected to prevent heart disease— but does not. Similarly, researchers had high hopes for an experimental drug that raises HDL, but instead of preventing heart attacks the drug wound up increasing the risk.
11) Part of the problem is that surrogate endpoints do not always reflect what’s happening to the whole patient. The disease being treated may be too complicated to gauge with just one tool, and the drug in question may have many more effects than the one being measured.
12) Avandia, for instance, does a good job of lowering blood sugar. But it also activates a whole array of genes, and can cause weight gain, fluid retention, heart failure, anemia and unfavorable changes in lipid levels in the blood, according to an editorial last week in The New England Journal of Medicine. It’s not clear whether the drug’s benefits will trump its risks in the long run.
Which of the following statements about surrogate endpoints is NOT right

A．Surrogate endpoints are more reliable because they are based on objective measures.
B．Surrogate endpoints are not always reliable because the disease being treated may be too complicated to gauge with just one tool.
C．Surrogate endpoints may help streamline the process of drug approval.
D．Surrogate endpoints do not always reflect the safety of a drug because it may have many more effects than the one being measured.

点击查看答案&解析

7.单项选择题Tell an investment banker that a picture bought in 1950 for $30,000 sold this month for $104.1 million and you will be unlucky if you fail to get his attention. That was the case with the portrait of a young boy by Picasso when Sotheby’s dispersed on May 5 the tail end of the famous collection formed by the late John Hay Whitney and his wife Betsy Cushing Whitney. Sales added up to almost $190 million within two hours.
If you then go on to explain that Whitney bought the 1905 portrait not for investment but for art’s sake, because he loved 19th- and 20th-century painting, you might well be greeted with a stare of compassionate irony.
Yet that was exactly so. Had the heir to a vast fortune consulted experts at the time, most would have advised against the acquisition. Received wisdom in the 1950s had it that it was Picasso’s breakthrough in modern art that made him truly important, i. e. his early Cubist work.
The Picasso case, which is probably the greatest success story ever in the art market, neatly illustrates the financial gamble that buying art represents. The biggest winners are not investors, but art lovers with a great eye who follow their intuition.
Art cannot be an investment because perception determines everything. No two works are ever identical. One Picasso does not equal another Picasso. On May 6, one day after the Whitney sale, Sotheby’s was offering another five Picassos. All fetched different prices.
That night the market was on a roll and two of the Picassos sold extremely well. Even so, their diverging fates illustrate the impossibility of predicting prices. Presale calculations are frequently belied, up or down. "Le Nu Accroupi" (describing a seated woman), dated "21/24.6.59," was expected to bring $3 million to $4 million plus the 12 percent sale charge. Furious bidding sent it climbing to $11,768,000.
The second of the two most expensive Picassos sold within the expected price bracket, costing $14,792,000．"Le Sauvetage" ("The ReScue") was painted in November 1932．This is seen as a seminal year. Why did it not arouse enthusiasm in proportion to the "Nu Accroupi" and increase the estimate by 250 percent
One reason, in favor of the "Nu Accroupi", is that the figure of the seated woman is distorted in a manner that best fits the general public’s idea of what Picasso’s art looks like. The face broken up in separate halves that can be read as seen sideways or full front is typical of this stereotype even if in reality Picasso was the most versatile artist of his time.
Another reason works against "Le Sauvetage". A jarring note is introduced by the spiky rendition of the human figures. Moreover, some deem the composition to be loose. Others, by contrast, praise its rhythm. The argument can go on indefinitely. In short, no complete agreement is ever reached over the aesthetic characterization of a painting. Nor is there ever total agreement over the assessment of its importance relative to the artist’s oeuvre. How good within the 1932 style "Le Sauvetage" is will be seen differently by different viewers.
Cubism was a crucial phase of Picasso’s art in the view of virtually all art historians today and yet the-1909 to 1914 revolutionary works are not always well received by the public at auction.
Immediately before the "Nu Accroupi", a large charcoal sketch of a man’s head done by Picasso in 1909 in his first Cubist manner reflecting the impact that African sculpture had on its emergence came up with a $400,000 to $600,000 estimate. The drawing came from a European estate, and works with an estate provenance generally do well because they have long been out of sight. Moreover, it had previously passed through the hands of one of the greatest 20th-century dealers, Heinz Berggruen, while he was based in Paris. All to no avail. The drawing fell unsold, probably too ungainly for its art historical importance to weigh sufficiently in its favor. But both these characterizations are a matter of perception.
The last 4th paragraph tells us that ______.

A．art collectors are mostly astute professionals
B．the public tend to simplify something not easily understood with a stereotype
C．Picasso never changed his unique painting style
D．the "Nu Accroupi" is Picasso’s best work

点击查看答案&解析

8.填空题

参考答案：pay

9.单项选择题1)People with diabetes have too much sugar in their blood, so a drug that lowers blood sugar ought to be a good treatment, right
2) Maybe not. Consider the diabetes drug Avandia, or rosiglitazone, which was approved in 1999．it lowers blood sugar, and about a million people in the United States have been talking it for Type 2 diabetes, the most common form of the disease. But last week, doctors reported that Avandia might increase the risk of heart attacks.
3) Heart disease is a major complication of diabetes, so a drug that could make the risk even worse is bad news indeed.
4) The jury is still out on Avandia. Meanwhile, patient advocates and some politicians and researchers are already denouncing it, and the Food and Drug Administration has issued a tepid "safety alert" telling patients to ask their doctors what to do while the agency "is carefully weighing several complex sources of data." Avandia’s manufacturer, GlaxoSmithKline, insists it is safe. Personal injury lawyers are advertising on the Internet for clients who think they were injured by the drug.
5) What happened here reflects a larger question—the tricky problem of how to judge whether a drug is safe and effective. Avandia was approved because it lowered blood sugar, and seemed safe in clinical trials.
6) But the real test of whether a drug is any good is how are the patients Not their blood tests or X-rays or EKGs, but the people themselves, and not after just six months, but after years, especially if they have a chronic disease and will be talking medicine for the rest of their lives. Are those talking the drug more or less likely than people not talking it to have heart attacks, die or develop heart disease or other illnesses
7) The problem is, it can take a long time and a lot of patients—and, therefore, a lot of money — to get a real picture of health and survival. That is especially true for something like heart disease, which develops slowly and is so common that it may be hard to detect a small increase in risk. Studies might have to go on for years instead of months, and include far more than the few thousand patients in whom drugs are typically tested before they get approved.
8) So instead of waiting to see if people die or have heart attacks, drug companies have looked for other traits that seem to correlate with health and survival and that could stand in as a yardstick—objective measures like blood pressure, cholesterol (胆固醇) levels, blood sugar or tests of heart function. Researchers call these measurements "surrogate endpoints," and the F. D．A．has encouraged companies to find surrogates that could reliably predict how patients would fare. These kinds of tests are seen as a way to streamline the drug approval process.
9) But reliable surrogates are hard to find. There are plenty of endpoints that in theory should do the job, but do not. Tumor size, for instance: there are drugs that Can shrink tumors without prolonging a patient’s life. Bone density is another example. Fluoride can increase it in people whose skeletons have thinned from osteoporosis (骨质疏松症) , so fluoride should prevent fractures. But it doesn’t, in fact, it makes fractures more likely, because it turns bones brittle.
10) Heart rhythm can also be deceptive. Certain medicines can stabilize dangerous, abnormal heartbeats in people who have had heart attacks—and yet have been found to increase their odds of dying. Cholesterol levels do not always tell the whole story, either. Hormone treatment in women after menopause (绝经期) can raise HDL (高密度脂蛋白) , the so-called good cholesterol, and so was expected to prevent heart disease— but does not. Similarly, researchers had high hopes for an experimental drug that raises HDL, but instead of preventing heart attacks the drug wound up increasing the risk.
11) Part of the problem is that surrogate endpoints do not always reflect what’s happening to the whole patient. The disease being treated may be too complicated to gauge with just one tool, and the drug in question may have many more effects than the one being measured.
12) Avandia, for instance, does a good job of lowering blood sugar. But it also activates a whole array of genes, and can cause weight gain, fluid retention, heart failure, anemia and unfavorable changes in lipid levels in the blood, according to an editorial last week in The New England Journal of Medicine. It’s not clear whether the drug’s benefits will trump its risks in the long run.
As to the issue of drug approval, ______.

A．to judge whether a drug is safe enough should rely on objective measures
B．drug companies usually study for years to prove the safety and effectiveness of a drug
C．drug companies prefer surrogate endpoints in the process of drug approval because F.D.A.encourages them to do so
D．drug companies rely heavily on surrogated endpoints because this way of measurement takes less time and money

点击查看答案&解析

10.单项选择题They have been concerned with the following terms EXCEPT______.

A．millions of instructions per second
B．discount
C．remote connection
D．management committee

点击查看答案

延伸阅读

你可能感兴趣的试题