TOEFLライティング練習模試04
Read the passage below. You have 3 minutes to read through:
Hydrogen-based fuel-cell Engines
Car manufacturers and governments have eagerly been seeking a replacement for the internal combustion engine as an automobile’s main source of power. The most promising alternative source is currently the hydrogen-based fuel-cell engine which uses electricity created by hydrogen to power the car. There are several advantages to fuel-cell engines over the internal-combustion engine and will probably replace them soon.
The main problem with internal-combustion engines is that they rely on petroleum. Petroleum is a finite resource. At some point in the future, the supply of oil in the Earth’s crust will be exhausted. On the other hand, fuel-cell engines use hydrogen fuel for motive power. Hydrogen cannot easily be depleted and is found in various plentiful resources including natural gas and water. This makes hydrogen fuel cells a better environmentally-friendly alternative to conventional fossil fuels.
Also, fuel-cell engines are particularly attractive as an alternative power source for cars because they will solve several of the world’s pollution problems. By oxidizing molecular hydrogen, the only direct by-product of their energy generation is water, which means they could significantly reduce pollution and man-made greenhouse gases. On the other hand, carbon monoxide, nitrogen oxides, and hydrocarbons are released when fuel is burned in an internal combustion engine.
Finally, fuel-cell engines will become economically competitive due to the reduced cost of operating them. A fuel-cell automobile is almost twice as efficient at fuel use as an internal-combustion automobile. This means that it only requires half of the fuel energy to go the same distance as an internal-combustion powered car.
Listen to the audio below related to the article you just read.
Directions: Give yourself 20 minutes to plan and write your response.
Your response is judged on the quality of the writing and on how well it presents the points in the lecture and their relationship to the reading passage. Typically, an effective response will be 250 to 300 words.
You may view the reading passage while you respond.
- Summarize the point made in the lecture and explain how the speaker cast doubt on specific points made in the reading passage.
Independent Writing
Read the question below. Give yourself 30 minutes to plan, write, and revise your essay.
Typically, an effective response will contain a minimum of 350 words.
- Some universities now offer their courses on the Internet so that people can study online. In your opinion, is this a positive or negative development?
Sample Answer
Both the reading and the lecture discuss alternative fuel sources, namely, hydrogen-based fuel-cell engines. While the reading claims that this fuel source is advantageous, the lecturer identifies several issues with the use of hydrogen and provides three reasons as to why it is not a good choice.
First, in the reading, hydrogen is described as an attractive resource because it is an infinite supply of energy. However, the lecturer argues that due to the technological challenges of both obtaining and storing hydrogen, it is impractical to replace internal-combustion engines with fuel-cell engines.
Second, the reading makes a claim about hydrogen being environmentally-friendly. The lecturer refutes this. He says that even though fuel-cell engines would produce less pollution, the hydrogen manufacturing process would generate pollution when purifying the hydrogen. Moreover, he feels that this would not solve long-term problems with pollution.
Finally, while the author of the reading argues that the fuel-efficient hydrogen-based engines will cost less to operate, the professor refutes this concept. He cites the extremely expensive materials required to manufacture the engine, such as platinum, as being the source of the expense. Furthermore, he states that past attempts to replace materials this way have not been successful.
In conclusion, although the reading and the lecture are both about alternative fuel sources, the three main points made in the reading about the benefits of using hydrogen-based fuel-cell engines are challenged by the lecturer’s counterpoints.
In recent years, a small but growing number of universities have put their courses online for people to study. In my opinion, while some people feel there could be a few drawbacks, I believe the positives far outweigh the negatives.
On the face of it, the main disadvantage to utilizing online content to study is that it results in less meaningful support. This means that students mostly communicate with their professors through writing rather than face-to-face. Therefore an issue or problem that may be discussed in one session, may take weeks to discuss online, not to mention the potential for misunderstandings. Additionally, online education fails to account for the support from peers. For instance, in a classroom environment, peers may learn from each other’s questions, support each other, or more easily engage in teamwork and collaborate together. Online learners, on the other hand, may seldom encounter their classmates.
Notwithstanding these negatives, online university courses are a positive development in several ways. For a start, learners have much greater flexibility while studying. This means they while many may have jobs, families, or other commitments, by studying online, they can participate at any time, anywhere, and at their own speed. Secondly, the cost is much cheaper due to few overheads such as reduced support. That’s why universities can afford to offer first-class content at a price accessible to everyone. Most importantly, online courses are available to everyone. When online, everyone can enroll, irrespective of age, background, or even location, meaning that literally, anyone can do an online course in the way that works best for them.
In conclusion, while I consider that some downsides to distance learning do exist, I believe it to be a considerably positive development in general.
Transcript
Hydrogen-based fuel-cell Engines
| P: | The reading correctly points out the problems with oil-powered cars. Yes, oil is a finite resource with a by-product that can harm the environment, but it is also way too optimistic about hydrogen-based fuel-cell engines. Hydrogen is not the solution to these problems. |
| First of all, it is not as easily available as the passage implies. While it is present in common substances such as water, it is not able to be used directly from that form. To be used in a fuel-cell engine, the hydrogen has to be obtained in a pure liquid state. Pure liquid hydrogen is an artificial substance that is very hard to produce and store because it must be stored at extremely cold temperatures. This would take a very elaborate cooling technology making it impractical as a fuel source. | |
| Also, using hydrogen doesn’t solve the pollution problems associated with cars because it creates a lot of pollution to get the pure hydrogen in the first place. The large amount of energy required to extract the pure hydrogen from water or natural gases is achieved by burning coal or oil which in turn creates a lot of pollution. Even though the cars would no longer create pollution, the factories making the fuel source would still pollute. | |
| Finally, there isn’t necessarily a cost savings once you consider how expensive it is to manufacture the fuel-cell engine. The cost is so high because fuel-cell engines require platinum, a very rare and expensive metal, to manufacture the components allowing for the chemical reaction that produces the electricity to power the automobile. Attempts to replace platinum with cheaper materials have proven unsuccessful. |