综合写作9

  Reading

  Car manufacturers and governments have been eagerly seeking a replacement for the automobile's main source of power, the internal-combustion engine. By far the most promising alternative source of energy for cars is the hydrogen-based fuel-cell engine, which uses hydrogen to create electricity that, in turn, powers the car. Fuel-cell engines have several advantages over internal-combustion engines and will probably soon replace them.

  One of the main problems with the internal-combustion engine is that it relies on petroleum, either in the form of gasoline or diesel fuel. Petroleum is a finite resource; someday, we will run out of oil. The hydrogen needed for fuel-cell engines cannot easily be depleted. Hydrogen can be derived from various plentiful sources, including natural gas and even water. The fact that fuel-cell engines utilize easily available, renewable resources makes them particularly attractive.

  Second, hydrogen-based fuel cells are attractive because they will solve many of the world's pollution problems. An unavoidable by-product of burning oil is carbon dioxide, and carbon dioxide harms the environment. On the other hand, the only byproduct of fuel-cell engines is water.

  Third, fuel-cell engines will soon be economically competitive because people will spend less money to operate a fuel-cell engine than they will to operate an internal-combustion engine. This is true for one simple reason: a fuel-cell automobile is nearly twice as efficient in using its fuel as an automobile powered by an internal-combustion engine is. In other words, the fuel-cell powered car requires only half the fuel energy that the internal-combustion powered car does to go the same distance.

  Listening

  Professor:

  The reading is correct in pointing out the problems associated with oil-powered cars. Yes, oil is a finite resource, and yes, burning oil harms the environment. However, the reading is way too optimistic in its assessment of hydrogen-based fuel-cell engines. Hydrogen is not the solution to these problems.

  First, hydrogen is not as easily available as the passage indicates. Although it's present in common substances like water, it's not directly useable in that form. For using a fuel-cell engine, hydrogen must first be obtained in a pure liquid state. This pure liquid hydrogen is a highly artificial substance. It's technologically very difficult to produce and store liquid hydrogen. For example, it must be kept very very cold at minus 253 degrees Celsius. Imagine the elaborate cooling technology that's required for that! So hydrogen is not such a practical and easily available substance, is it?

  Second, using hydrogen would not solve the pollution problems associated with cars. Why? Producing pure hydrogen creates a lot of pollution. To get pure hydrogen from water or natural gas, you have to use a purification process that requires lots of energy that's obtained by burning coal or oil. And burning coal and oil creates lots of pollution. So although the cars would not pollute, the factories that generated the hydrogen for the cars would pollute.

  Third, there won't necessarily be any cost savings when you consider how expensive it is to manufacture the fuel-cell engine. That's because fuel-cell engines require components made of platinum, a very rare and expensive metal. Without the platinum components in the engine, the hydrogen doesn't undergo the chemical reaction that produces the electricity to power the automobile. All the efforts to replace platinum with a cheaper material have so far been unsuccessful.

  一、阅读听力要点概括

  Reading Passage

  Main points: Fuel-cell have several advantages over internal-combustion engines.

  Sub point 1: Internal-combustion relies on petroleum and Hydrogen is clean and renewable.

  Sub point 2: Full cells can solve pollution problems.

  Sub point 3: Full-cell soon can be economically competitive.

  Lecture

  Attitude: R is too optimistic. (Hydrogen-based full-cell is not the solution.)

  Sub Point 1: Hydrogen not easily available. (Need in a pure liquid state, need very cold temperature.)

  Sub Point 2: Hydrogen does not solve the pollution. ( Producing creates a lot of pollution, Burning coal or oil.)

  Sub Point 3: No cost saving since expensive to manufacture. (Require platinum, expensive.)

  Answers

  二、范文逐段赏析

  Paragraph 1

  The lecturer points out several problems with the use of hydrogen-based fuel-cell engines which support her claim that substituting them for internal-combustion engines is technologically unfeasible, environmentally unfriendly, and economically unviable.

  此段功能:

  (Listening passage后文提到用L代替)

  (Reading passage后文用R代替)

  开头段作者总结到L指出(氢燃料电池引擎)替换(内燃机引擎)科技上不能实现,环境上不友好,而且经济上不合适。

  此段结构:

  这一句话,巧妙的用L的反对逻辑,引出了论证问题的三个方面。把总结L,总结R和表明逻辑轻巧的锁在了一句话里。

  Paragraph 2

  First, the lecturer states that it is impractical to replace internal-combustion engines with fuel-cell engines because using the latter requires hydrogen in a pure liquid form, which is technologically challenging to both obtain and store. However, the reading passage argues that because hydrogen can be extracted from many sources including water, fuel-cell engines powered by this infinite source of energy are an extremely attractive alternative.

  此段功能:

  在第一点technology unfeasible的论证上。作者复述L觉得电池替换内燃是不现实的,因为电池需要液态氢,而液态氢非常难制取和储存。在R里,R只想到了氢气可以从很多来源从提炼比如水,所以认为燃料是无限的,这种想法很有吸引力。

  此段结构:

  此段为分总结构,作者先阐明L认为这个替换是不现实的,因为某些原因。第二句中作者复述了R本来认为的观点,作为对比。

  Paragraph 3

  Second, the lecturer refutes the claim in the reading that hydrogen cells are environmentally friendly. She argues that although engines that use hydrogen cells produce less pollution, the manufacturing of hydrogen cells generates large amounts of harmful by-products due to the burning of fossil fuels in the purification process.

  此段功能:

  在第二点environmental unfriendly 辩论上,作者直接陈述L认为R所说的电池很环保是错误的。L解释虽然电池引擎不会产生太多污染,但是制造电池引擎的提纯过程消耗了大量的化石燃料也是不环保的。

  此段结构:

  此段为总分结构。作者大略总结了一下R的观点并说L持反对意见,随后列举所有的反对R的证据。

  Paragraph 4

  Third, although the reading suggests that hydrogen-based engines are more fuel-efficient and thus economically competitive than internal-combustion engines, the lecturer argues that such an advantage is undermined by the fact that fuel-cell engines are extremely expensive to manufacture, requiring the addition of platinum, a very rare and expensive material.

  此段功能:

  在最后一点economically unviable的论证上。作者说,虽然R认为电池引擎的燃料效率比内燃机高,但是L举出制造电池引擎需要用到铂这种贵金属,使得其燃料优势被抵消了。

  此段结构:

  此段为分分结构,用了一个although,先引出R的论点,再举一系列L的证据来反斥R的论点,达到了反驳的效果。

  三、范文全篇总评

  1、 逻辑结构

  全文遵从总分结构,开头段一个难度不高的长句,很好的揉合了逻辑关系,LR双方观点和告诉了读者接下来三个分段的主题。

  在分论段的论述中,作者很好的陈述了双方观点,根据反对逻辑关系,列出双方的针对证据,结构清晰。

  2、语言表达

  本文难度主要来自生词,但是作者用词准确,其中可以借鉴的词句有:

  1. The lecturer /points out several problems(表达反对关系)/ with /the use of hydrogen-based fuel-cell engines(论文主要事件)/ which support her claim that /substituting them for internal-combustion engines(B的意见)/ is /technologically unfeasible, environmentally unfriendly, and economically unviable.(三个分论点)/

  Unfeasible: 行不通的

  Unviable: 不能独立的

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