题目内容
商店经销某种商品，每周进货量X(公斤)与顾客对该种商品的需求量Y(公斤)是相互独立的，且都在区间10，20上服从均匀分布．商店每售出该种商品一公斤可得利润1000元，若需求量超过进货量，商店可从其他商店调货，这时每公斤商品获利500元，若需求量不到进货量，商店因积压，每公斤商品损失500元，试计算商店经销该种商品每周所得利润的期望值．
查看答案
搜索结果不匹配？点我反馈
更多问题
Sadness isn’t manly—this Eric Weaver knew. When depression engulfed this New York police sergeant, it took a different guise: a near-constant state of anger. "One minute I’d be okay and the next minute I’d be screaming at my kids and punching the wall," he recalls. "My kids would ask, ’What’s wrong with Daddy Why’s he so mad all the time’" For years, Weaver didn’t know what was wrong. Weaver’s confusion about what tortured him was not unusual. Roughly a third of the 18 million or more Americans who suffer depression each year are men. Yet all too often, experts say, men fail to recognize the symptoms and get the treatment they need. For years, experts suspected that gender makes a big difference in depression. Studies from New York to New Zealand have repeatedly found the same startling statistic: About twice as many women as men suffer from depression. That finding was considered one of the bedrock facts of modern mental health. Yet it has recently come under attack from critics who are concerned about underreporting of male depression. William Pollack, Director of the Center for Men at McLean Hospital, is leading the charge against the well-entrenched depression gender gap. He argues that men’s rate of depression may be nearly equal to women’s. Just look at suicide rates, he says: Male suicides outnumber females four to one. That ratio "is way too high to say that men’s depression numbers are so low," he notes. Pollack and others contend that male depression goes unrecognized because, unlike the female version, it often doesn’t fit the textbook signs—at least in the early stages. Clinical depression at later stages looks much the same in both sexes. But in the prelude to a breakdown, that deepening despair is often expressed in very different ways. Instead of being weepy, men are more apt to be irritable and angry—moods that aren’t included in the classic diagnostic tests. "Their sadness and helplessness are hidden behind a mask of anger," says Pollack. "Men tend to act out" to avoid dealing with uncomfortable feelings, adds Fredric Rabinowitz, a psychologist who works primarily with men. If they feel bad, they’re apt to get into fights on the job or at home, withdraw from family and friends, become obsessed with work or hobbies. Most significantly, men often turn to drinking or drugs. Men have two to four times the rate of substance abuse problems as women, and Pollack contends that if this was recognized as a sign of depression, the gender gap would substantially narrow. According to the passage, Mr. Pollack believes that men facing depression______.
Logging is destroying the rainforests Every second, 1 hectare of the world’’s rainforest is destroyed. That equals to two football fields. An area the size of New York City is lost every day. In a year, that adds up to 31 million hectares — more than the land area of Poland. This alarming rate of destruction has serious consequences for the environment; scientists estimate, for example, that 137 species of plant, insect or animal become extinct every day due to logging. In British Columbia, where, since 1990, thirteen rainforest valleys have been clear-cut, 142 species of salmon have already become extinct, and the habitats of grizzly bears, wolves and many other creatures are threatened. Logging, however, provides jobs, profits, taxes for the government and cheap products of all kinds for consumers, so the government is reluctant to restrict or control it. Canadian forests are especially under threat Much of Canada’’s forestry production goes towards making pulp and paper. According to the Canadian Pulp and Paper Association, Canada supplies 34% of the world’’s wood pulp and 49% of its newsprint paper. If these paper products could be produced in some other way, Canadian forests could be preserved. Recently, a possible alternative way of producing paper has been suggested by agriculturalists and environmentalists: a plant called hemp. Hemp has been cultivated throughout history Hemp has been cultivated by many cultures for thousands of years. It produces fiber which can be made into paper, fuel, oils, textiles, food, and rope. For many centuries, it was essential to the economies of many countries because it was used to make the ropes and cables used on sailing ships; colonial expansion and the establishment of a world-wide trading network would Not have been possible without hemp. Nowadays, ships’’ cables are usually made from wire or synthetic fibres, but scientists are now suggesting that the cultivation of hemp should be revived for the production of paper and pulp. According to its supporters, four times as much paper can be produced from land using hemp rather than trees, and many environmentalists believe that the large-scale cultivation of hemp could reduce the pressure on Canada’’s forests. It is illegal to grow hemp However, there is a problem: hemp is illegal in many countries of the world. This plant, so useful for fiber, rope, oil, fuel and textiles, is a species of cannabis, related to the plant from which marijuana (大麻) is produced. In the late 1930s, a movement to ban the drug marijuana began to gather force, resulting in the eventual banning of the cultivation Not only of the plant used to produce the drug, but also of the commercial fiber-producing hemp plant. Although both George Washington and Thomas Jefferson grew hemp in large quantities on their own land, any American growing the plant today would soon find himself in prison—despite the fact that marijuana cannot be produced from the hemp plant, since it contains almost NO THC (the active ingredient in the drug). Recently, many people have been working to legalize hemp In recent years, two major movements for legalization have been gathering strength. One group of activists believes that all cannabis should be legal—both the hemp plant and the marijuana plant — and that the use of the drug marijuana should not be an offense. They argue that marijuana is not dangerous or addictive, and that it is used by large numbers of people who are not criminals but productive members of society. They also point out that marijuana is less harmful than alcohol or tobacco. The other legalization movement is concerned only with the hemp plant used to produce fiber; this group wants to make it legal to cultivate the plant and sell the fiber for paper and pulp production. This second group has had a major triumph recently: in 1997, Canada legalized the farming of hemp for fiber. For the first time since 1938, hundreds of farmers are planting this crop, and soon we can expect to see pulp and paper produced from this new source. ________argued that marijuana is not dangerous or addictive.
建立下表科目，并装入期初余额 期初余额表 科目编号 科目名称 借方余额 贷方余额 1001 库存现金 34000 1002 银行存款 109400 100201 工行存款 16600 1131 应收款账 25000 1243 库存商品 30000 1221 包装物 30000 1603 在建工程 2121 应付账款 20000 3101 实收资本 25000 5101 主营业务收入 100000 5502 管理费用 6601 销售费用 83400 合计 228400 228400
In America and Europe magazine publishers have a common headache: total circulation is either flat or declining slightly as people devote more time to the internet, and an ever greater share of advertising spending is going online. Magazine units are mostly a drag on growth for their parents. Time Inc, the world’ s biggest magazine company, has to fend off rum ours that its parent, Time Warner, will sell it. People in the industry expect that Time Warner will soon sell IPC Media, its British magazine subsidiary. The business model for consumer magazines is under pressure from several directions at once, both online and off. Magazines have become more expensive to launch, and the cost of attracting and keeping new subscribers has risen. In America newsstand sales have been worryingly weak, partly because supermarkets dominate distribution and shelf-space is in short supply. The internet’s popularity has hit men’s titles the hardest. FHM, the flagship "lads" magazine of Emap—a British media firm, for instance, lost a quarter of its circulation in the year to June. Not long ago consumer magazines were Emap’s prize asset, but slowing growth from the division contributed to the company’s decision to put itself up for sale. Men’s magazines are in trouble in most developed-world markets as people have quickly switched from magazines to online services. There are good reasons why magazine owners should not feel pessimistic, however. For readers, many of the pleasing characteristics of magazines—their portability and glossiness, for instance— cannot be matched online. And magazines are not losing younger readers in the way that newspapers are. According to a study by the digital arm of Ogilvy Group, appetite for magazines is largely unchanged between older "baby boomers" and young "millennials". On the advertising side, magazines are faring much better than newspapers, which are losing big chunks of revenue as classified advertising shifts online. Advertisers like the fact that in many genres, such as fashion, readers accept and value magazine ads and even consider them part of the product. Unfortunately, magazine publishers have been slow to get onto the internet. "Eighteen months ago the internet was something they worried about after 4pm on Friday," says Peter Kreisky, a consultant to the media industry, "but now it’s at the heart of their business model. " To their credit, however, big magazine firms are doing far more than reproducing their print products online. They offer people useful, fun services online—Lagardere’ s Car and Driver website, for instance, offers virtual test drives, and Better Homes and Gardens online has a 3D planning tool to help people redesign their homes. When going onto the internet, big magazines______.
微信支付 
支付宝支付