欢迎来到新航道官网!新航道-用心用情用力做教育!
400-619-6509

首页>托福>托福TPO>托福TPO9综合写作文本(含听力+阅读)

托福TPO9综合写作文本(含听力+阅读)

来源:新航道 原创作者:常州新航道 浏览:0 发布日期:2018-01-29 14:09

返回列表

小编为大家整理了全网最全托福TPO综合写作文本,希望帮助考生更好的备考,争取理想成绩,实现留学梦想。下面是托福TPO9写作部分。
TPO 09
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.

阅读调查

阅读文本, 您觉得有帮助吗?

您需要内部讲义资料吗?

您最近有出国留学的打算吗?

您的姓名
您的电话
提交获取帮助

托福TPO课程中心

查看更多 >
  • 托福入门班(3-8人) 1. 学前托福考试成绩在80... 36小时 详情咨询 在线咨询
  • 托福强化班(3-8人) 1. 学前托福考试成绩在80... 72小时 详情咨询 在线咨询
咨询热线
400-619-6509
集团客服电话
400-097-9266

常州新航道学校:常州市钟楼区延陵西路119号南大街商业步行街2楼201-207室(星巴克咖啡泰富店对面)