Alcohol use is the number one drug problem among young people. It's easy to understand why. For adults, alcohol is legal, widely 1 in American culture and easily 2 . Many kids can get a drink right in their own homes. 3 are drinking younger and more frequently than 4 , often beginning around age 13, according to studies. The average number of alcoholic drinks among college students is five on a single 5 , according to a recent survey. Among those younger 21, it is 5.5 drinks, and among 6 21 and older, it is 4.2 drinks. Young people almost always begin drinking because of 7 pressure, in an attempt to be accepted and 8 in the group. According to the U.S. Surgeon General, more than half of junior and senior high school students drink alcoholic 9 . More than 40 percent of those who drink admit to drinking when upset, 31 percent admit to drinking 10 , 25 percent admit to drinking when 11 and 25 percent admit to drinking to get " 12 ." This is a 13 , serious problem 14 college campuses today. In 1997 Harvard University's School of Public Health surveyed students at 130 colleges for a college 15 study and found about two of every five college students 16 in binge drinking. 17 binge drinkers at college were 22 times more 18 than non-binge drinkers to have problems, 19 missed classes, falling behind in school work, getting in trouble or hurt and engaging in 20 sexual activity.

In 1693

During the past generation

Could HIV, the virus that causes AIDS

For decades a titan has towered over America's shopping landscape. Walmart is not just the world's biggest retailer but the biggest private employer and, by sales, the biggest company. Last year its tills rang up takings of $482 billion, about twice Apple's revenue. But now the beast of Bentonville must cope with an unfamiliar sensation. After ruling as the undisputed disrupter of American retailing, Walmart finds itself being disrupted. The source of the commotion is online shopping, specifically online shopping at Amazon. E-commerce accounted for $1 in every $10 that American shoppers spent last year, up by 15% from 2014. Amazon's North American sales grew at about twice that rate. Walmart's share of America's retail sales, which stands at 10.6%, is still more than twice Amazon's, but it peaked in 2009 at nearly 12%. In January Walmart said it would close 154 American stores. It may need to shut more. Walmart's "supercentres" once offered an unmatched combination of squeezed prices and expansive choice, but this formula is losing its magic. Discounters and other competitors are rivalling Walmart's low prices at the same time as Amazon's warehouses can beat its range. Amazon is also offering something different. Whereas Walmart has strived to help Americans save money, Amazon is obsessed with helping them save time. Amazon has become a new kind of big-box retailer, with warehouses placed strategically around America to speed deliveries to customers. Innovations such as Dash, which let you press a button in your kitchen to order soap or coffee, could turn Amazon from an online store into something like a utility. Walmart is fighting back. It is spending billions in the hope of growing even larger. It is offering more goods to more customers, in stores and online. With its legendary attention to detail, it is making its operations even more efficient. For instance, it will save more than 35 truckloads of buttercream icing this year, after spotting that its bakers were leaving too much icing in the bottom of their tubs. By using 27 different boxes rather than i2 to deliver online goods, the firm reckons it can save 7.2m cubic feet of cardboard boxes a year. Last month sunny results sent up its share price by 10%. Yet far from offering comfort to other retailers hoping to knit together physical and online businesses, Walmart's fightback shows how hard it will be for them to repel Amazon. From the first paragraph we know ______.

Growing cooperation among branches of tourism has proved valuable to all concerned

Back in 2002 Ben Bernanke

The amount of greenhouse gases we've already pumped into the atmosphere has irreversibly bound us to a certain amount of warming over the next several decades. That means climate change isn't a problem for tomorrow—the effects are happening now. Already raining patterns seem to be changing, making some drier areas even drier, and rainy regions even wetter. As warmer temperatures creep northward, so do insects and other pests that are adapted to the heat. The population of the tiny mountain pine beetle, which infests pine trees in the Rocky Mountain region, used to be controlled by freezing winters. But as temperatures have warmed over the past decade, the mountain pine beetle's territory has spread, destroying millions of acres of Canadian pines. The pine beetle infestation represents the unique challenges that warming will pose for land conservation managers on the front lines of the battle against it. Generations of American conservationists have fought to preserve wildlife and to keep nature pure in the face of a growing population and pollution. But global warming threatens to change all that, by altering the very foundation on which the conservation movement was built. What good is a wildlife reserve if the protected animals can't live there, because climate change pushes them out? What difference does it make to defend trees from logging, if global warming will allow a new pest to ruin the whole forests? The answer is to adapt the way we practice wildlife and land conservation to climate change. There's a term for this—adaptive management. We need to begin making moves today to adapt to changes that warming will bring decades hence. "Climate change will affect anything, you name it," said Lara Hansen of EcoAdapt. "We need to change the way we allocate resources and protect livelihoods." That means that the way we've been carrying out conservation—picking the right land spaces and playing goalie—won't work anymore, as climate change keeps moving the target. Conservationists will have to work even harder, trying to minimize non-climate-related threats to land and species even as the human population grows by billions. Regardless of what we do, the changes will be coming fast and the future will bring increased drought, heat waves, rainstorms, extinctions and more. We need to begin cutting our carbon immediately, but we need to adapt now as well. The world is changing because of us; to save what's left, we'll have to change too. From the passage we can learn that the pine beetle ______.

In an ideal world

Hunger is no novelty

If you are worried about climate change

Directions: em>Seat occupation has become a common phenomenon in your university

A. The health dangers of eating meat B. Respect the rights of animals C

Helping yourself to a cup of coffee may seem like a small, everyday thing. But not if you are quadriplegic. Unlike paraplegics, for whom the robotic legs described in the previous article are being developed, quadriplegics have lost the use of all four limbs. Yet thanks to a project organised by John Donoghue of Brown University, in Rhode Island, and his colleagues, they too have hope. One of the participants in his experiments, a 58-year-old woman who is unable to use any of her limbs, can now pick up a bottle containing coffee and bring it close enough to her mouth to drink from it using a straw. She does so using a thought-controlled robotic arm fixed to a nearby stand. It is the first time she has managed something like that since she suffered a stroke, nearly 15 years ago. Arms are more complicated pieces of machinery than legs, so controlling them via electrodes attached to the skin of someone's scalp is not yet possible. Instead, brain activity has to be recorded directly. And that is what Dr. Donoghue is doing. Both his female participant and a second individual, a man of 66 also paralysed by a stroke, have worked with him before, as a result of which they have had small, multichannel electrodes implanted in the parts of the motor cortexes of their brains associated with hand movements. The woman's implant was put there in 2005; the man's five months before the latest trial, described in a paper just published in em>Nature/em>. Dr. Donoghue and his team decoded signals from their participants' brains as they were asked to imagine controlling a robotic arm making preset movements. The volunteers were then encouraged to operate one of two robot arms by thinking about the movements they wanted to happen. When the software controlling the arms detected the relevant signals, the arms moved appropriately. Dr. Donoghue and his colleagues have thus shown that a mechanical arm can be controlled remotely by the brain of a person with paralysis. Controlling a true prosthetic-an arm that is attached to the individual's body-will be trickier, but in time even that may be possible. In the meantime, a robotic arm attached to (say) a wheelchair will be a real boon. For people who have little or no ability to move their arms Dr Donoghue's work promises liberation in the form of quotidian action that the able-bodied take for granted. Dr. Donoghue's experiments include ______.

Directions: Your pen pal Peter will come to Beijing for a visit. For some reasons

Choice is a fundamental American value that often lies at the center of heated political discussions

It's not that we thought things were free

A. MBA program boom in South Africa B. Current assessment of MBA programs C

阅读理解Text 2A new survey by Harvard University finds more than two-thirds of young Americans disapprove of President Trumps use of Twitter