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“An independent technician” in the first sentence of the second paragraph means
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According to Bleakly，before buying a used car aU the inspection work can
Electric Backpack
Backpacks 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 and the Marine Biological Laboratory in Woods Hole3，Mass. ，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，night-vision goggles，and other battery-powered devices to get around and do their work．The backpack’s electricity-generating feature could dramatically reduce the amount of a wearer’s load now devoted to spare batteries，report Rome and his colleagues in the Sept．9 Science．
The backpack ’s electricity-creating powers depend on springs used to hang a cloth pack from its metal flame．The frame. sits against the wearer’s back，and the whole pack moves up and down as the person walks． A gear mechanism converts vertical movements of the pack to rotary motions of an electrical generator，producing up to 7.4 watts．
Unexpectedly．tests showed that wearers of the new backpack alter their gaits in response to the pack ’s oscillations．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 non—electric versions of the backpack．
The backpack could be especially useful for soldiers，scientists，mountaineers，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，a11 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!
第 1 题 Backpacks are convenient because
A．speak B．have C．1ink D．put
The Operation Of InternationaI Airlines
International airlines have rediseovered the business traveler，the man or woman who regularly jets from country to country as part of the job．This does not neeessarily mean that airlines ever abandoned their business travelers． Instead，eompanies like Lufthansa and Swissair would right argue that they have always catered best for the executive class passengers．But many airlines could be accused of concentrating too heavily in the recent past on attracting passengers by volume，often at the expense of the regular traveler．Too often，they have seemed geared for quantity rather than quality．
Operating a major airline is essentially a matter of finding the right mix of passengers．The airlines need to fill up the back of their wide—bodied jets with low fare passengers，without forgetting that the front end should he filled with people who pay suhstalltially more for their tickets．
It is no coincidence that the two major airline bankruptcies were among the companies specializing in cheap flights．But low fares require consistently full aircraft to make flights economically viable，and in the recent recession the volume of traffic has not grown．Equally the large number of airlines jostling for the available passengers has created a huge excess of capacity．The net result of excess capacity and cut—throat competition driving down fares had been to push some airlines into collapse and leave many others hovering on the brink．
Against this grim background，it is no surprise that airlines are turning increasingly towards the business travelers to improve their rates of return．They have invested much time and effort to establish exactly what the executive demands for sitting apart from the tourists．
High on the list of priorities is punctuality；an executive’s time is money．In—flight service is another area where the airlines are jostling for the executive’s attention．The free drinks and headsets and better food are all part of the lure．
Another development has been the accent of seating arrangements．Regular travelers have become well versed in the debate about seat pitch-the amount of room between each passenger．And first-class passengers are now offered sleeperettes， which，for long journeys，make it possible to snatch a proper night’s sleep．Sleeperettes have proved so popular that they will soon become universal
in the front end of most aircraft．
The airlines are also trying to improve things on the ground．Executive lounges are commonplace and intended to make the inevitable waiting between flights a little more bearable．Luggage handling is being improved．Regrettably，there is little the airlines can do to speed up the boring immigration and customs process，which manages to upset and frustrate passengers of all classes in every continent．
Although it is the airlines’intention to attract executive passengers from their rivals，the airlines themselves would nonetheless like to change one bad habit of this kind of traveler—the expensive habit of booking a flight and then failing to turn up．The practice is particularly widesptead in Europe，where businessmen frequently book return journeys home one on severnl flights．
第 46 题 According to the passage，in operating airlines it is essential to________．
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