25.The average citizen dislikes the motorcyclists because______

A.all motorcycles are wild young men

B.all motorcycles are irresponsible young men

C.all motorcycles are lawless young men

D.they frequently look dirty,they often make an unpleasant noise,and their appearance contributes to people's terrible imagination

B

No more batteries,no more chargers and no more wires.This is the future promised by  "wireless power".a means of broadcasting electricity through the air to laptops,iPods and other gadgets(小器具)without the need for cables and sockets(插座).

Wireless lighting,audio speakers and digital picture frames are expected to be among the first commercial products exhibited in Las Vegas this week at the International Consumer Electronics Show,the world's biggest gadgets tradeshow.

Experts believe this is just the beginning and that eventually wireless electricity could do for battery life what WiFi(局域网)did for,the Internet.In a world without wires,laptop users in cafes and airport terminals(终点站)would be inside an "electricity hotspot" and no longer have to delve an awkwardly located socket.

"You'd be able to buy.a desk that charged any gadget placed on it,or power any PC you put on top," said James Holland,editor of gadgets website Eleetricpig.co.uk."If each room had wireless power,you'd know that once you walked through the front door your nmbile would start charging up-even while still in your bag or pocket.You'd never need to hunt for the right charger again."

Among the companies showcasing the ambitions technology at CES is PowerBeam.Its system turns electricity into an invisible laser,then beams(传播) it as heat,across the room to a solar cell that conveys it back into dectricity.

David Graham,the co-founder of PowerBeam,said:"We're going to delete the word  'recharge' from the English dictionary.If your,cell phone is recharging on your desk.all day,you won't be thinking about.it." The Silicon Valley company can currently use a laser to generate about 1.5 watts of power to_a solar.cell 10 meters away.This,sould be enough to power an electronic speaker or small LED(二极管) lights,but not enough to operate a laptop,which requires about 30 to 50 watts.However,Graham said that the technology could comfortably be scaled up(提高).

PowerBeam insists its laser does not lead to a risk to users' health because it is simply moving heat from one place to another.Graham said that,if someone walked through the beam,itwould shut down within a thousandth of a second,then restart once the path is clear.The technology also promises because it would only power products when needed.

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