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Electric BackpackBackpacks are convenient. They can hold your books, your lunch, and a change of clothes, leaving your hands free to do other things. Someday, if you don"t mind carrying a heavy load, your backpacks might also power your MP3 player, keep your cell phone running, and maybe even light your way home.Lawrence C. Rome and his colleagues from the University of Pennsylvania in Philadelphia have invented a backpack that makes electricity from energy produced while its wearer walks. In military actions, search-and-rescue operations, and scientific field studies, people rely increasingly on cell phones, global positioning system (GPS) receivers (接收器), night-vision goggles (夜视镜), and other battery-powered devices to get around and do their work. The backpack"s electricity-generating feature could greatly reduce the amount of a wearer"s load now devoted to spare batteries.The backpack"s electricity-creating powers depend onspringsused to hang a cloth pack from its metal frame. The whole pack moves up and down as the person walks. A special mechanism converts movements of the pack to electricity, which can be as much as 7.4 watts.Unexpectedly, tests showed that wearers of the new backpack alter their gaits (步法) in response to the pack"s oscillations (摆动), so that they carry loads more comfortably and with less effort than they do ordinary backpacks. Because of that surprising advantage, Rome plans to commercialize both electric and nonelectric versions of the backpack.The backpack could be especially useful for soldiers, scientists, mountaineers (登山运动员), and emergency workers who typically carry heavy backpacks. For the rest of us, power-generating backpacks could make it possible to walk, play video games, watch TV, and listen to music, all at the same time. Electricity-generating packs aren"t on the market yet, but if you do get one eventually, just make sure to look both ways before crossing the street! The sentence "if you do get one eventually, just make sure to look both ways before crossing the street!" implies ______.
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Freezing to Death for BeautyPeople in Beijing wear a lot of clothing during winter to fend off (抵御) the cold. In the United States, however, people wear 1 , partly because the car is the primary mode of transportation. Cars take 2 straight to their workplaces, which are heated well. The American diet is full of calories, so their 3 can afford to burn heat more quickly.Fewer layers of clothing give people the opportunity to stay 4 . Lots of Yale girls wear skirts 5 when it"s 10 degrees Centigrade outside. Some of them at least wear boots, tights, and leg-warmers. Some, however, really just go for the look 6 the risk of health. These girls have no pants to prevent their 7 , and no socks to protect their feet. A mini skirt and a pair of stilettos (细高跟鞋) are all that they wear.Typically, the ones pursuing fashion are 8 , with little body fat. Just by the nature of their bodies, they are already at a disadvantage compared with normal people in 9 weather. I have always 10 , whenever I pass these girls, how they manage to refrain from shivering and just smile like spring had arrived.And then there are the guys. The girls can be said to 11 health for beauty. But why do guys 12 so little It is not like, once they take off some layers, they suddenly become better-looking. They are not exactly being fashionable when they 13 wear sporty (花哨的) shorts and shower slippers in the midst of winter. It"s not cute(喜人的).Of course, people have the freedom to look whatever 14 they want. I am just surprised that, given the vast difference between winter and summer temperatures in Connecticut, they can still 15 like they are partying on the beach in the middle of February.
Freezing to Death for BeautyPeople in Beijing wear a lot of clothing during winter to fend off (抵御) the cold. In the United States, however, people wear 1 , partly because the car is the primary mode of transportation. Cars take 2 straight to their workplaces, which are heated well. The American diet is full of calories, so their 3 can afford to burn heat more quickly.Fewer layers of clothing give people the opportunity to stay 4 . Lots of Yale girls wear skirts 5 when it"s 10 degrees Centigrade outside. Some of them at least wear boots, tights, and leg-warmers. Some, however, really just go for the look 6 the risk of health. These girls have no pants to prevent their 7 , and no socks to protect their feet. A mini skirt and a pair of stilettos (细高跟鞋) are all that they wear.Typically, the ones pursuing fashion are 8 , with little body fat. Just by the nature of their bodies, they are already at a disadvantage compared with normal people in 9 weather. I have always 10 , whenever I pass these girls, how they manage to refrain from shivering and just smile like spring had arrived.And then there are the guys. The girls can be said to 11 health for beauty. But why do guys 12 so little It is not like, once they take off some layers, they suddenly become better-looking. They are not exactly being fashionable when they 13 wear sporty (花哨的) shorts and shower slippers in the midst of winter. It"s not cute(喜人的).Of course, people have the freedom to look whatever 14 they want. I am just surprised that, given the vast difference between winter and summer temperatures in Connecticut, they can still 15 like they are partying on the beach in the middle of February.
We must get to the root of the problem.
Time to Stop Traveling by AirTwenty-five years ago a young British man called Mark Ellingham decided that he wanted a change of scenery. So he went to Australia, stopping off in many countries in between. He also decided to write about the experience and produced a guide for other travelers making similar journeys.In 1970, British airports were used by 32 million people. In 2004, the figure was 216 million. In 2030, according to government forecasts, it will be around 500 million. It"s a growth driven by the emergence of low cost airlines, offering access to all parts of the world for less than ￡100.This has made a huge contribution to global warming. One return flight from Britain to the US produces the same carbon dioxide (二氧化碳) as a year"s motoring (驾车). A return flight to Australia equals the emissions (排放) of three average cars for a year. And the pollution is released at a height where its effect on climate change is more than double that on the ground.Mark Ellingham built his business on helping people travel. Now he wants to help people stop—at least by air.He is calling for a ￡100 green tax on all flights to Europe and Africa, and ￡250 on flights to the rest of the world. He also wants investment to create a low-carbon economy, as well as a halt to airport expansion.Mark Ellingham"s commitment is important because his readers aren"t just the sort of young and adventurous people who would happily jump on a plane to spend a weekend exploring a foreign culture. They are also the sort of people who say they care about the environment. It"s a debate that splits people down the middle.The tourist industry has responded by offering offsetting (补偿) schemes. A small increase in the price of a ticket is used to plant trees.But critics say that it is not enough to just be carbon neutral. We should be actively cutting back on putting greenhouse gases into the atmosphere. And for the average person, making a plane journey will be his or her largest contribution to global warming. It may be good to repair the damage we do. But surely it is better not to do the damage in the first place. Traveling from Britain to any other part of the world may cost you less than ￡100.
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