您家门前的大街上整天车水马龙。不过,您并未感到厌烦,反到挺高兴,因为每过一辆汽车,您家的电费就少了一点儿。楼下川流不息的行人也让您感愉快,随着匆匆的脚步,他们发出的电帮助点亮了街灯。这些人甚至也在帮助他们自己,当他们赶路的时候顺便给手提电脑或移动电话充电。 The street in front of your house is full of traffic. However, you are not bored, but rather happy, because every car, your home’s electricity costs a little less. Pedestrians who flow downstairs also make you feel happy. With hurried steps, the electricity they sent helped light up the street lights. These people are even helping themselves and charging their laptops or mobile phones when they are on the road.