If I see one more article about how wonderful alternative energy is compared to oil, I will flip(翻页). Alternative energy sources can be good---- very good in fact. And it’s pretty obvious that we’re going to need them, and that our dependence on oil is a Bad Thing. But accepting that does not mean accepting that any kind of alternative energy is a good thing. To be a good thing, it has to have three properties: 1) It has to help reduce our dependence on oil, 2) It has to be no worse for the environment, and 3) It has to be economically practical. Many of the things praised meet one or even two of those properties. Solar panels, for example. They can reduce our need for oil, at least in certain regions, and they’re certainly not bad for the environment. But they’re expensive. If you spend the money to make your home solar-powered, you probably won’t get back your costs for at least 15 years, which approaches the lifespan of the panels. Certainly we need to clean up our act big time and find workable sources of alternative energy. But we also have to keep in mind that every one of these alternative-energy sources comes at a cost, which is something people seem to forget. They hear the phrase “alternative energy” and automatically assume it’s got to be good. But green isn’t always good, and oil isn’t always bad. One seemingly “green” technology that pops up again and again is electric cars. It is praised by well-meaning people as good for the environment and a way to reduce our oil dependence, especially as oil prices continue to rise. Electric cars are dirty. In fact, not only are they dirty, they might even be more dirty than their gasoline-powered cousins. People in California love to talk about “ zero-emissions 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 “zero-emissions” cars are likely coal-burning 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 fue) 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 gas- powered 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 lace. 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:Which of the following statements will the writer support? A．Any kind of alternative energy is a good thing. B．Alternative energy is bound to take the place of oil. C．People should have an objective view towards alternative energy. D．Solar panel is a good example of alternative energy that meets three properties. 小题2:What does “ clueless” mean in Paragraph 7? A．People see the California Greens everywhere. B．People in California love to talk about zero-emissions vehicles. C．People in California love to have their roofs covered with solar cells. D．People there have no idea that so far electrically mainly comes from burning coal, oil, etc. 小题3:What is the main idea for the text? A．Green technology is not always green. B．Alternative energy is economically practical. C．Electric cars are not clean at all. D．Gasoline is an efficient way to power a vehicle. 小题4:According to the text, electric cars ___________. A．are more environmentally friendly B．burn more fuel than gas-powered ones C．are very good at cleaning up when things are not too concentrated D．are poisonous for a long time and will eventually end up in a landfill 小题5: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．zero-emissions vehicles should be chosen to protect our environment D．electric cars are now the dominant vehicle compared with gasoline-powered cousins