評論
打印
Now listen to part of lecture on the topic you just read about.
現(xiàn)在來聽一段有關(guān)你剛剛讀到的話題的演講。
The reading is correct in pointing out the problems associated with oil-powered cars.
閱讀文章在指出與燃油汽車有關(guān)的問題時(shí)是對的。
Yes, oil is a finite resource, and yes, burning oil harms the environment.
是的，石油是有限的資源，而且，燃燒石油有害環(huán)境。
However, the reading is way too optimistic in its assessment of hydrogen-based fuel-cell engines.
然而，閱讀部分對于氫動力燃料電池發(fā)動機(jī)的評價(jià)卻過于樂觀。
Hydrogen is not the solution to these problems.
氫不是解決這些問題的方法。
First, hydrogen is not as easily available as the passage indicates.
首先，氫不像文章中提到的那樣容易獲得。
Although it's present in common substances like water, it's not directly useable in that form.
盡管它呈現(xiàn)在像水這樣的平常物質(zhì)中，但它在那個(gè)狀態(tài)下不是直接可用的。
For using a fuel-cell engine, hydrogen must first be obtained in a pure liquid state.
使用燃料電池發(fā)動機(jī)，首先必須要獲得純液態(tài)氫。
This pure liquid hydrogen is a highly artificial substance.
這種純的液體氫是高度人工的物質(zhì)。
It's technologically very difficult to produce and store liquid hydrogen.
生產(chǎn)和儲存液氫技術(shù)上來說非常困難。
For example, it must be kept very very cold at minus 253 degrees Celsius.
比如，它必須被儲存在非常非常冷的溫度，零下253攝氏度。
Imagine the elaborate cooling technology that's required for that!
試想一下那個(gè)需要的精密制冷技術(shù)。
So hydrogen is not such a practical and easily available substance, is it?
所以氫不是一種現(xiàn)實(shí)的容易獲得的物質(zhì)，是嗎？
Second, using hydrogen would not solve the pollution problems associated with cars.
第二，使用氫不能解決汽車所帶來的污染問題。
Why? Producing pure hydrogen creates a lot of pollution.
為什么？生產(chǎn)純氫會產(chǎn)生很多污染。
To get pure hydrogen from water or natural gas,
要從水或者天然氣中獲得氫，
you have to use a purification process that requires lots of energy that's obtained by burning coal or oil.
必須使用純化工序，這個(gè)工序需要大量的通過燃燒煤炭和石油獲得熱量。
And burning coal and oil creates lots of pollution.
燃燒煤炭和石油會造成很多污染。
So although the cars would not pollute, the factories that generated the hydrogen for the cars would pollute.
所以，盡管汽車不會污染，但是生產(chǎn)汽車所用的氫的工廠會污染。
Third, there won't necessarily be any cost savings when you consider how expensive it is to manufacture the fuel-cell engine.
第三，未必能節(jié)約成本，如果你考慮一下生產(chǎn)燃料電池發(fā)動機(jī)有多貴的話。
That's because fuel-cell engines require components made of platinum, a very rare and expensive metal.
那是因?yàn)槿剂想姵匕l(fā)動機(jī)需要鉑金制成的零部件，鉑金是一種稀有而貴重的金屬。
Without the platinum components in the engine,
發(fā)動機(jī)里沒有鉑金部件的話，
the hydrogen doesn't undergo the chemical reaction that produces the electricity to power the automobile.
氫不會進(jìn)行化學(xué)反應(yīng)來發(fā)電以供汽車動力。
All the efforts to replace platinum with a cheaper material have so far been unsuccessful.
目前所有用便宜一點(diǎn)的材料來替換鉑金的努力都不成功。
