托福考试

【单选题】Listening 8 "Environmental ScienceClass"
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What is this lecture mainly about
A、An overview of fuel cell technology
B、A、process for producing fuel cells
C、A、comparison of fuel cell models
D、Some problems in fuel cell distribution
网考网参考答案：A
网考网解析：
[解析] 40-45 Narrator: Listen to part of a lecture in an environmental science class. Professor: Hydrogen is the most recent and, I’d say, one of the most promising, in a long list of alternatives to Q40 petroleum. Some of the possibilities include batteries, methanol, natural gas, and, well, you name it. But Q41 hydrogen fuel cells have a couple of advantages over some of the other options. First of all, they’re really quiet, and they don’t pollute the atmosphere. Besides that, hydrogen is the most abundant element in the universe, and it can be produced from a number of sources, including ammonia, or... or even water. So, it’s renewable, and there’s an almost unlimited supply. Okay. Now fuel cells represent a radical departure from the conventional internal combustion engine and even a fairly fundamental change from electric battery power. Like batteries, fuel cells run on electric motors; however, batteries use electricity from an external source and store it for use in the battery while the fuel cells create their own electricity through a chemical process that uses hydrogen and oxygen from the air. Are you with me Look, by producing energy in a chemical reaction rather than through combustion, a fuel cell can convert, say 40-60 percent of the energy from the hydrogen into electricity. And when this ratio is compared with that of a combustion engine that runs at about half the efficiency of a fuel cell, well, it’s obvious that fuel cell technology has the potential to revolutionize the energy industry. So, fuel cells have the potential to generate power for almost any kind of machinery or equipment that fossil fuels run, but, the most important, urn, let’s say goal, the goal of fuel cell technology is the introduction of fuel cell powered vehicles. Internationally, the competition is fierce to commercialize fuel cell cars. I guess all of the leading automobile manufacturers worldwide have concept cars that use fuel cells, and some of them can reach speeds of as high as 90 miles per hour. Even more impressive is the per tank storage capacity. Can you believe this Some of those cars can run for 220 miles between refills. But many of those cars were designed decades ago, so... what’s the holdup Well, the problem in introducing fuel cell technology is really twofold. In the first place, industries will Q44 have to invest millions, maybe even billions of dollars to refine the technology—and here’s the real cost’the infrastructure to, uh, support the fueling of the cars. And by infrastructure, I mean basic facili- ties and services like hydrogen stations to refuel cars and mechanics who know how to repair them. I think you get the picture. And then, consumers will have to accept and use the new products powered by fuel cells. So, we’re going to need educational programs to inform the public about the safety and... and convenience of fuel cells, if we’re going to achieve a successful transition to fuel cell products. But, unfortunately, major funding efforts get interrupted. Here’s what I mean. When oil prices are high, then there seems to be more funding and greater interest in basic research and development, and more public awareness of fuel cells, and then the price of oil goes down a little and the funding dries up and people just go back to using their fossil fueled products. And this has been going on for more than thirty years. Some government sponsored initiatives have created incentives for fuel cell powered vehicles but Q42 probably one of the most successful programs, at least in my opinion, is, uh, the STEP program, which is an acronym for the Sustainable Transportation Energy Program. STEP is a demonstration project sponsored by the government of Western Australia. Now, in this 查看试题解析出处>>