Electric cars are dirty.In fact，not only are they dirty，they might even be more dirty than their gasoline­powered cousins. People in California love to talk about “zero­emissions vehicles”， but _ people _ in _ California _ seem _ to _ be _ clueless _ about _ where _ electricity _ comes _ from .Power plants mostly use fire to make it.Aside from the new folks who have their roofs covered with solar cells，we get our electricity from generators.Generators are fueled by something—usually coal，oil，but also by heat generated in nuclear power plants.There are a few wind farms and geothermal(地热的) plants as well，but by far we get electricity mainly by burning something. In other words，those “zero­emissions” cars are likely coal­burning cars.It’s just because the coal is burned somewhere else that it looks clean.It is not.It’s as if the California Greens are covering their eyes—“If I can’t see it，it’s not happening.” Gasoline is an incredibly efficient way to power a vehicle；a gallon of gas has a lot of energy in it.But when you take that gas(or another fuel) and first use it to make electricity，you waste a nice part of that energy，mostly in the form of wasted heat—at the generator，through the transmission(传送) lines，etc. A gallon of gas may propel your car 25 miles.But the electricity you get from that gallon of gas won’t get you nearly as far—so electric cars burn more fuel than gas­powered ones.If our electricity came mostly from nukes；or geothermal，or hydro，or solar，or wind，then an electric car truly would be clean.But for political，technical，and economic reasons，we don’t use much of those energy sources. In addition，electric cars’ batteries which are poisonous for a long time will eventually end up in a landfill.And finally，when cars are the polluters，the pollution is spread across all the roads.When it’s a power plant，though，all the junk is in one place.Nature is very good at cleaning up when things are too concentrated，but it takes a lot longer when all the garbage is in one spot. 小题1:What does the underlined part mean in Paragraph 2? A．People see the California Greens everywhere. B．People in California love to talk about zero­emissions vehicles. C．People in California love to have their roofs covered with solar cells. D．People in California have no idea that so far electricity mainly comes from burning coal，oil，etc. 小题2:What is the main idea of the text? A．Electric cars are not clean at all. B．Electric cars are better than gasoline­powered ones. C．People cast doubts on electric cars’ batteries. D．Gasoline is an efficient way to power a vehicle. 小题3:The electricity we get from a gallon of gas may make our car run ________. A．not less than 25 miles B．as far as 50 miles C．as far as 25 miles D．not more than 25 miles 小题4:It can be inferred from the text that ________. A．being green is good and should be encouraged in communication B．electric cars are not clean in that we get electricity mainly by burning something C．zero­emissions vehicles should be chosen to protect our environment D．electric cars are now the dominant vehicle compared with gasoline­powered cousins