Sports and games make our bodies strong, prevent us from getting too fat, and keep us healthy. But these are not their only use. They give us valuable practice in making eyes, brain and muscles work together. In tennis, our eyes see the ball coming, judge its speed and direction and pass this information on to the brain. The brain then has to decide what to do, and to send its orders to the muscles of the arms, legs, and so on, so that the ball is met and hit back where it ought to go. All this must happen with very great speed, and only those who have had a lot of practice at tennis can carry out this complicated chain of events successfully. For those who work with their brains most of the day, the practice of such skills is especially useful.Sports and games are also very useful for character-training. In their lessons at school, boys and girls may learn about such virtues as unselfishness, courage, discipline and love of one’s country, but what is learned in books cannot have the same deep effect on a child’s character as what is learned by experience. The ordinary day-school cannot give much practical training in living, because most of the pupils’ time is spent in classes, studying lessons. So it is what the pupils do in their spare time that really prepares them to take their place in society as citizens when they grow up. If each of them learns to work for his team and not for himself on the football field, he will later find it natural to work for the good of his country instead of only for his own benefit. The "complicated chain of events" refers to()
A. the passing of information and making of the decisions
B. the meeting and hitting back of the bail
C. the coordinated movements of our eyes, brain and muscles
D. a lot of practice before playing tennis
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 nonspecialist 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 (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. Which of the following is NOT true
A. Each page can be given a score that reflects its importance.
B. In the beginning of rating a page’s relative importance, all pages are given the same score.
C. 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.
D. One page’s score is given totally to another page it links to.