大學英語自學教程 unit 19

[00:00.00]Unit 19 text A [00:04.78] Animals at Risk:Who Cares ? [00:07.31]動物處境危險：誰來關心？ [00:09.85]An animal species becomes extinct [00:12.47]當一種動物不能在每一代 [00:15.10]when it fails to produce enough young in each generation [00:18.08]都生育出足夠的后代以便與死亡率相平衡時， [00:21.05]to keep pace with the death-rate. [00:23.09]它就逐漸滅絕。 [00:25.13]We can tell from fossil evidence in rocks [00:27.51]從化石中我們可以找到證據(jù)， [00:29.88]that many living species have become extinct over the millions of yearssince life began. [00:34.12]說明自有生命以來在千百萬年的時間里，許多生物物種已經(jīng)成為滅絕。 [00:38.35]It is a natural process and extinction is the fate of any animal that has [00:42.37]這是一化，或者其競爭對手更有適應性， [00:46.39]specialized too far to change when its environment changes, [00:49.42]比它更強大， [00:52.45]or has to compete with a better--adapted and more powerful animal. [00:55.69]那么這種動物便命中洽談室 要滅絕。 [00:58.93]Because of remarkable technical developments during the past few centuries, [01:02.81]近幾個世紀以來，由于科學技術落后的世大發(fā)展， [01:06.69]man has destroyed or nearly destroyed some species [01:10.11]人類以超過動物園繁殖后代的速度來捕殺動物， [01:13.53]by killing them at such a rate that they couldn't produce enough offspring, [01:16.92]或以驚人的速度徹底改變動物的自然環(huán)境， [01:20.30]or by completely changing their natural environment at surprising speed. [01:24.28]從而使一些動物物種滅絕或幾乎滅絕。 [01:28.27]A number of examples can be given of the way [01:31.14]自然環(huán)境正在迅速改變的例子可以舉出許多， [01:34.01]in which natural environments are being rapidly changed Amazonia,for instance. [01:38.10]亞馬遜尼亞國家公園便是一例。 [01:42.19]There is every likelihood that many species of animal swill be made extinct [01:46.06]完全有可能，許多種動物由于自然植被在這些 [01:49.92]because of these and similar clearances of natural vegetation. [01:53.19]或類似的地方被破壞殆盡而陷于滅絕。 [01:56.45]Large numbers of animals have been hunted and killed for food. [01:59.94]大量動物作為肉食而被獵殺。 [02:03.43]The North American buffalo is a case of the near-extinction of a species through hunting. [02:07.61]北美洲水牛便是因捕獵而成為瀕臨滅絕物種的一個例子。 [02:11.79]Often the numbers are so great the hunter smay not realize the danger. [02:15.76]動物數(shù)量常常很大，捕獵者可能意識不到危險的存在。 [02:19.73]But even when the danger is widely publicized, [02:22.25]但即使人們廣泛宣傳這種危險性 [02:24.77]the financial rewards for the hunters [02:27.00]由于經(jīng)濟利益太大， [02:29.24]may be so great that they choose to ignore the threat to the species. [02:32.41]捕獵者會置物種滅絕的危險于不顧。 [02:35.59]Attitudes like this have led to hunters killing animals for furs [02:38.86]這種態(tài)度已使捕獵者為了取得皮毛、 [02:42.14]for ivory or merely for ornaments. [02:44.52]象牙或純粹為了獲得裝飾品而獵殺動物； [02:46.90]A slight variation on this is when tourists hunt animals for trophies. [02:50.78]與此稍有不同的是，旅游者獵殺動物是為了獲取紀念品。 [02:54.65]Magnificent creatures such as lions and tigers [02:57.89]像獅子和老虎之類的大型動物 [03:01.13]have been hunted out of existence in some parts of the world. [03:04.36]在世界某些地方已被殺盡。 [03:07.59]It is important to realise, [03:09.82]不過，還需要了解的是， [03:12.05]thoughthat animals are sometimes killed out of fear. [03:14.38]有些動物被殺是因為人們害怕它們。 [03:16.70]Big cats are killed in this way. [03:19.18]有時某些大型貓科動物就是這樣死于非命的。 [03:21.67]And animals are sometimes killed out of a wish to reduce numbers [03:25.09]有時人們捕殺動物是為了減少其數(shù)量 [03:28.51]to help the species to survive. [03:30.43]以使該物種得以生存。 [03:32.35]The killing of the Canadian seals is claimed to be for this purpose, [03:36.18]捕殺加拿大海豹據(jù)說就是這樣的目的， [03:40.00]and the use of their skins for furs is only a by-product. [03:43.43]而利用其皮毛僅是副產(chǎn)品而已。 [03:46.85]Many people are concerned about animals and wildlife conservation [03:49.79]許多人關心著對動物和野生生物的保護。 [03:52.72]One way to preserve species under threat of extinction [03:55.51]保護瀕臨滅絕的物種 [03:58.29]what ever the cause--is to remove them to zoos and parks and breed them there. [04:02.42]不管何種原因造成的——其辦法之一是將這些物種遷移到動物園和公園里飼養(yǎng) [04:06.54]There is always the chance that enough offspring will be born [04:09.52]總是有可能將其后代繁殖到足夠數(shù)量 [04:12.50]to return them one day to their natural environment--provided it still exists, [04:16.57]以便有朝一日放回到自然環(huán)境中去——如果這種物種還存在 [04:20.65]and that hunters don't kill them again! [04:22.88]而且人類不再捕殺它的話！ [04:25.12]Another method is to protect the animals in their natural environment [04:28.54]另一種辦法是建立野生動物禁獵區(qū)或野生動物園并且雇用禁獵人員看守 [04:31.96]by creating wildlife reserves and parks and using game wardens to look after them. [04:36.39]以此保護動物生活在自然的環(huán)境里。 [04:40.82]But the parks are large, [04:42.64]但是野生動物園范圍大， [04:44.47]the wardens few and the determination of hunters very great. [04:47.70]看護人員少，而捕獵者又敢于挺而走險。 [04:50.93]Early in 1980 wardens and hunters clashed in East Africa. [04:54.70]1980年初看護人與捕獵人在東非發(fā)生沖突，捕獵者配備現(xiàn)代化武器，死了好幾個人。 [04:58.48]The hunters were armed with modem weapons and several people were killed. [05:02.35]在自然的或接近自然的環(huán)境里觀看野生動物會是一種很大的樂趣。 [05:06.23]There is great pleasure in watching wildlife in natural or nearnatural environments [05:14.78]and tourism can add to the income of countries. [05:17.66]這樣的旅游業(yè)能給國家增加收入 [05:20.55]The animals are still resources--but in a very different form. [05:23.97]動物仍是資源——只是另一種形式上十分不同的資源罷了。 [05:27.39]Text B [05:30.45]The Killer Smogs [05:32.88]致命煙霧 [05:35.31]On the night of December 1,1930, [05:38.19]1930年12月1日晚， [05:41.08]a dense fog moved over the Meuse Valley, in Belgium. [05:44.20]一片濃霧籠罩著比利時默茲河流域， [05:47.32]Many factories in the valley poured smoke and fumes into the foggy air. [05:50.96]那里的許多工廠將大量煙塵排入霧氣蒙蒙的空中， [05:54.59]This created a dark smog of smoke and fog combined. [05:58.01]這樣形成了煙與霧的混合物：黑色的煙霧。 [06:01.43]People in the valley began to cough and strain for breath. [06:04.55]那個地區(qū)的居民開始咳嗽，呼吸困難。 [06:07.67]The smog remained for four days. [06:10.05]煙霧持續(xù)了四天 [06:12.43]During that time, thousands of people became ill. [06:15.35]在此期間，有幾千人得病。 [06:18.28]The hospitals were filled with patients. [06:20.76]醫(yī)院里住滿了病人， [06:23.24]Sixty people died. [06:25.16]有60人死亡， [06:27.08]Most of them were older persons with heart and lung problems. [06:30.32]多數(shù)為患有心肺疾病的老年人。 [06:33.56]Finally, a heavy rain washed away the smog. [06:36.68]最后一場大雨將煙霧沖洗掉。 [06:39.80]Scientists studied the courses of the disaster. [06:42.48]科學研究了疾病的原因， [06:45.16]They concluded that the illnesses and deaths [06:47.68]得出的結(jié)論是疾病和死亡都是煙霧中的 [06:50.20]were coursed by chemicals in the smog. [06:52.33]化學物質(zhì)所致。 [06:54.46]The first reported event of this kind in the United Stateshappened in Donora, [06:58.43]美國首次報告的這類事件發(fā)生在多諾拉， [07:02.40]a factory town in a valley near Pittsburgh. [07:04.72]這是靠近匹茲堡的一個工業(yè)小鎮(zhèn) [07:07.05]In 1948, a killer smog made half of the population sickthere were 17 deaths. [07:11.67]1948年致人死命的煙霧使一半居民得病，17人死亡。 [07:16.30]Again, older people with lung or heart diseases were hit hardest. [07:19.98]同樣，患有肺病或心臟病的老年人受害最甚。 [07:23.66]London,England, has always been known for its "black fogs." [07:27.39]英國倫敦一向以“黑霧”而聞名。 [07:31.11]In the winter of 1952, a milky white fog rolled into the city. [07:34.79]1952年冬天，一股乳白色的大霧滾滾涌入這個城市。 [07:38.48]It soon turned into black smog as the smoke of the citypoured into the air. [07:42.11]隨著城市的煙塵排入天空，白霧很快變成黑色煙霧。 [07:45.74]It was so hard to see [07:47.87]看東西很困難， [07:50.00]that people had to walkin front of the buses to guide them. [07:52.79]人們不得不走在公共汽車前面為汽車引路。 [07:55.59]In this way, the most serious air pollution disaster in history began. [07:59.22]就這樣開創(chuàng)了歷史上最嚴重的空氣污染的災難。 [08:02.85]When it was over, more than 4,0130 peoplehad been killed by the thick black smog. [08:07.01]當這場災難結(jié)束時，有4000多人死于濃黑的煙霧。 [08:11.18]New York City has had several London-type smogs since 1950. [08:15.01]自1950年以來，紐約市發(fā)生過幾次倫敦式的煙霧。 [08:18.83]Each time, there were from 100 to 400 deaths caused by the smog. [08:22.87]每次煙霧都造成100至400人死亡。 [08:26.91]Although these smogs were not as deadly as London's, [08:29.64]雖然這些煙霧不像倫敦煙霧那么可怕， [08:32.37]New York City has the worst air pollution problem in the United States. [08:35.75]但紐約市的空氣污染問題在美國是最嚴重的 [08:39.13]In all the killer smogs, [08:41.35]在各種致人死命的煙霧中， [08:43.57]factories and homes poured smokeand fumes into the air from the furnaces. [08:47.26]有工廠和家庭爐灶里排放到空氣中的煙塵。 [08:50.94]The chemical fumes combined with the water droplets in the fog [08:54.03]化學煙塵與霧氣中的水珠結(jié)合 [08:57.13]to form harmful substances. [08:59.05]在一起形成有害物質(zhì)。 [09:00.97]These substances caused the illness of those who breathed the polluted air. [09:04.60]這些物質(zhì)便使吸入這種污染空氣的人得病。 [09:08.23]Usually,such harmful fumes rise into the upper airand are blown away by the wind. [09:12.46]這種有害煙塵通常會上升到空氣的上層，被風吹散。 [09:16.70]But sometimes there is an unusual weather condition [09:19.43]但有時有一種特殊的天氣狀況 [09:22.16]called a temperature inversion. [09:24.28]稱為溫度逆增。 [09:26.41]A layer of cold air remains near the ground as smoke and fumes pour into it [09:30.38]當煙塵排入空氣時，冷空氣層依然靠近地面， [09:34.35]This is covered by an upper layer of warm air that acts like a lid. [09:37.89]而在外層是暖空氣，就像一個蓋子。 [09:41.43]It prevents the polluted cooler air from rising. [09:44.22]外層暖空氣阻礙污染的冷空氣上升。 [09:47.00]The harmful fumes pile up and make people ill. [09:49.22]這樣，有害煙塵便聚集起來，使人得病。 [09:51.44]The smog may be so thick that airprts are closed [09:55.46]煙霧有可能很濃，使得機場被迫關閉， [09:59.48]and chains of collisions occur on the highways. [10:02.00]公路上會發(fā)生連續(xù)的撞車事故。 [10:04.53]Another type of smog occurs in Los Angeles. [10:07.31]還有一類煙霧出現(xiàn)在洛杉磯。 [10:10.09]Here the weather may be clear and sunny. [10:12.06]那里天氣晴朗，陽光燦爛。 [10:14.03]But stinging eyes and dry coughs show that harmful chemicals fill the air [10:17.51]但是人們干咳，眼睛刺痛，說明空氣里充滿有害化學物質(zhì)。 [10:20.98]The smog is due to invisible gases, mostly from automobile exhaust. [10:24.71]這種煙霧是由一些看不見的氣體，其中大部分是汽車廢氣造成的。 [10:28.43]Because these chemicals are changed by the sun high up in the air, [10:31.55]因為這些化學物質(zhì)被高空中的陽光照射而發(fā)生變化， [10:34.67]Los Angeles smog is called photochemical smog. [10:37.95]所以洛杉磯煙霧叫做光化煙霧。 [10:41.23]It contains automobile exhaust fumes [10:43.66]這種煙霧含有汽車排出的廢氣 [10:46.09]and nitrogen oxides changed by the sun's rays. [10:48.57]和被陽光照射后發(fā)生變化的氧化氮。 [10:51.05]Added to these are sulfur dioxide [10:53.18]除此之外，還有從工廠 [10:55.31]and other fumesfrom factories and oil refineries. [10:57.84]與煉油廠排放出來的二氧化硫和其他煙塵。 [11:00.38]Photochemical smog is found in many large cities all over the world. [11:03.76]全世界許多大城市都有光化煙霧。 [11:07.14]Killer smogs don't happen very often,fortunately. [11:10.17]幸虧致人死命的煙霧不常出現(xiàn)。 [11:13.20]But in many large cities, [11:15.28]但在許多城市，汽車廢氣、 [11:17.35]a combination of automobile exhaust fumeshome furnace smoke, [11:20.63]家用爐灶冒出的煙塵以 [11:23.91]and factory waste gases pours into the air. [11:26.43]及工廠廢氣都排放到空氣中。 [11:28.95]This may also happen in the suburbs,or out in the country, [11:32.19]這種情況也還可能出現(xiàn)在建有大型工廠的 [11:35.43]where large factories have been built. [11:37.51]郊區(qū)與離城市的農(nóng)村。 [11:39.59]A number of harmful substances have been found in the air there. [11:42.51]在這種氣體中存在一些有害物質(zhì)。 [11:45.44]When these substances are breathed in day after day, [11:47.92]人們?nèi)諒鸵蝗盏匚脒@些有害物質(zhì)， [11:50.40]the health of the population is affected. [11:52.46]身體健康受到了影響。

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