he world is not only hungry,but also thirsty for water. This may seem strange to you, since nearly 75 % of the earth's surface is covered with water. But about 97% of this huge amount is sea water, or salt water. Man can only drink and use the other 3% -- the fresh water that comes from rivers, lakes,underground, and other sources. And we cannot even use all of that, because some of it is in the form of icebergs and glaciers. Even worse, some of it has been polluted.
However, as things stand today, this small amount of fresh water, which is constantly being replaced by rainfall, is still enough for us. But our need for water is increasing rapidly-- almost day by day. Only if we take steps to deal with this problem now can we avoid a severe worldwide water shortage later on. A limited water supply would have a bad effect on agriculture and industry. Let me give you just one small exampie of how necessary water is to industry. Did you know that to produce a single ton of steel, it takes about 91, 000 liters of water?
We all have to learn how to stop wasting our precious water. One of the first steps we should take is to develop ways of reusing it. Experiments have already been done in this field, but only on a small scale. For us, the systems are as important as the spacecraft.
他世界不只是餓了，也渴了。這對(duì)你似乎很奇怪，因?yàn)榻?5%的地球表面被水覆蓋著。但約97%的數(shù)額巨大的海水，或咸水。人只能喝一杯，用另外3%個(gè)--來(lái)自河流、湖泊、地下和其他來(lái)源的淡水。我們甚至不能使用，因?yàn)樗囊徊糠质窃诒胶捅ǖ男纬伞８愕氖?，一些污染已?jīng)被污染了。
然而，今天的情況是，這少量的新鮮的水，這是不斷被雨水所取代，仍然是不夠的我們。但是我們對(duì)水的需求正在迅速增加--幾乎一天一天。只有我們采取措施來(lái)解決這個(gè)問(wèn)題，我們才能避免嚴(yán)重的全球水資源短缺。有限的供水對(duì)農(nóng)業(yè)和工業(yè)有不利的影響。讓我給你一個(gè)小的對(duì)流換熱的水是必要的行業(yè)。你知道生產(chǎn)一噸鋼材，它需要91，000升的水？
我們都必須學(xué)會(huì)如何停止浪費(fèi)寶貴的水。我們應(yīng)該采取的第一個(gè)步驟就是開(kāi)發(fā)利用它的方法。實(shí)驗(yàn)已經(jīng)完成，在這一領(lǐng)域，但僅在一個(gè)小規(guī)模。對(duì)于我們來(lái)說(shuō)，系統(tǒng)和航天器一樣重要。
However, as things stand today, this small amount of fresh water, which is constantly being replaced by rainfall, is still enough for us. But our need for water is increasing rapidly-- almost day by day. Only if we take steps to deal with this problem now can we avoid a severe worldwide water shortage later on. A limited water supply would have a bad effect on agriculture and industry. Let me give you just one small exampie of how necessary water is to industry. Did you know that to produce a single ton of steel, it takes about 91, 000 liters of water?
We all have to learn how to stop wasting our precious water. One of the first steps we should take is to develop ways of reusing it. Experiments have already been done in this field, but only on a small scale. For us, the systems are as important as the spacecraft.
他世界不只是餓了，也渴了。這對(duì)你似乎很奇怪，因?yàn)榻?5%的地球表面被水覆蓋著。但約97%的數(shù)額巨大的海水，或咸水。人只能喝一杯，用另外3%個(gè)--來(lái)自河流、湖泊、地下和其他來(lái)源的淡水。我們甚至不能使用，因?yàn)樗囊徊糠质窃诒胶捅ǖ男纬伞８愕氖?，一些污染已?jīng)被污染了。
然而，今天的情況是，這少量的新鮮的水，這是不斷被雨水所取代，仍然是不夠的我們。但是我們對(duì)水的需求正在迅速增加--幾乎一天一天。只有我們采取措施來(lái)解決這個(gè)問(wèn)題，我們才能避免嚴(yán)重的全球水資源短缺。有限的供水對(duì)農(nóng)業(yè)和工業(yè)有不利的影響。讓我給你一個(gè)小的對(duì)流換熱的水是必要的行業(yè)。你知道生產(chǎn)一噸鋼材，它需要91，000升的水？
我們都必須學(xué)會(huì)如何停止浪費(fèi)寶貴的水。我們應(yīng)該采取的第一個(gè)步驟就是開(kāi)發(fā)利用它的方法。實(shí)驗(yàn)已經(jīng)完成，在這一領(lǐng)域，但僅在一個(gè)小規(guī)模。對(duì)于我們來(lái)說(shuō)，系統(tǒng)和航天器一樣重要。