2017公共英語四級閱讀文章
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公共英語四級閱讀文章一
In the late 1960's, many people in North America turned their attention to environmental problems, and new steel-and-glass skyscrapers were widely criticized. Ecologists pointed out that a cluster of tall buildings in a city often overburdens public transportation and parking lot capacities.
Skyscrapers are also lavish consumers, and wasters, of electric power. In one recent year, the addition of 17 million square feet of skyscraper office space in New York City raised the peak daily demand for electricity by 120, 000 kilowatts —— enough to supply the entire city of Albany, New York, for a day.
Glass-walled skyscrapers can be especially wasteful. The heat loss (or gain) through a wall of half-inch plate glass is more than ten times that through a typical masonry wall filled with insulation board. To lessen the strain on heating and air-conditioning equipment, builders of skyscrapers have begun to use double-glazed panels of glass, and reflective glasses coated with silver or gold mirror films that reduce glare as well as heat gain. However, mirror-walled skyscrapers raise the temperature of the surrounding air and affect neighboring buildings.
Skyscrapers put a severe strain on a city's sanitation facilities, too. If fully occupied, the two World Trade Center towers in New York City would alone generate 2.25 million gallons of raw sewage each year —— as much as a city the size of Stanford, Connecticut, which has a population of more than 109, 000.
60 年代后期，許多北美人把注意力轉(zhuǎn)向了環(huán)境問題，那些嶄新的玻璃鋼摩天大樓受到了廣泛的批評。生態(tài)學(xué)家指出，城市中密集的高層建筑經(jīng)常給公共交通與停車場的承載能力造成過重的負擔(dān)。
摩天大樓還是電能的過度消費者與浪費者。最近的某一年，紐約市摩天寫字樓 1，700 萬英尺辦公面積的增加使電能的最高日需求量提高了120，000 千瓦。這些電能足以供紐約的整個奧爾巴尼市使用一天。
玻璃表面的摩天大樓特別地浪費。 通過半英寸的平板玻璃墻壁損失(或增加)的熱量是典型的加入絕緣板的石墻所允許的熱量損失(或 增加)的十倍以上。為了減輕取暖設(shè)備或空調(diào)設(shè)備的壓力，摩天大樓的建造者們已經(jīng)開始使用雙面上釉的玻璃鑲板和涂上了金色或銀色反光薄膜的反光玻璃，來減少強光照射和熱量的`增加;但是，鏡面的摩天大樓會提高周圍空氣的溫度并會對附近的建筑物產(chǎn)生影響。
摩天大樓也對城市的衛(wèi)生設(shè)施造成了沉重的壓力。單單紐約市的二個世界貿(mào)易中心大樓如果完全被占滿的話，每年就會產(chǎn)生2，250，000 加侖的污水。這相當于康涅狄格州的斯坦福市這 樣大的城市一年所產(chǎn)生的污水量，而康州的斯坦福市擁有109，000 人口。
公共英語四級閱讀文章二
The preservation of embryos and juveniles is a rate occurrence in the fossil record. The tiny, delicate skeletons are usually scattered by scavengers or destroyed by weathering before they can be fossilized. Ichthyosaurs had a higher chance of being preserved than did terrestrial creatures because, as marine animals, they tended to live in environments less subject to erosion. Still, their fossilization required a suite of factors: a slow rate of decay of soft tissues, little scavenging by other animals, a lack of swift currents and waves to jumble and carry away small bones, and fairly rapid burial. Given these factors, some areas have become a treasury of well-preserved ichthyosaur fossils.
The deposits at Holzmaden, Germany, present an interesting case for analysis. The ichthyosaur remains are found in black, bituminous marine shales deposited about 190 million years ago. Over the years, thousands of specimens of marine reptiles, fish and invertebrates have been recovered from these rocks. The quality of preservation is outstanding, but what is even more impressive is the number of ichthyosaur fossils containing preserved embryos.
Ichthyosaurs with embryos have been reported from 6 different levels of the shale in a small area around Holzmaden, suggesting that a specific site was used by large numbers of ichthyosaurs repeatedly over time. The embryos are quite advanced in their physical development; their paddles, for example, are already well formed. One specimen is even preserved in the birth canal. In addition, the shale contains the remains of many newborns that are between 20 and 30 inches long.
Why are there so many pregnant females and young at Holzmaden when they are so rare elsewhere? The quality of preservation is almost unmatched and quarry operations have been carried out carefully with an awareness of the value of the fossils. But these factors do not account for the interesting question of how there came to be such a concentration of pregnant ichthyosaurs in a particular place very close to their time of giving birth.
胚胎與幼體被保存下來在化石記錄中是少見的事情。微小纖細的骨骼通常在石化前就被食腐肉的動物拆散了，或者被風(fēng)化作用破壞掉了。魚龍比起陸地的動物有更大的幾率被保存下來，因為它們作為海洋動物常生活在腐蝕性較小的環(huán)境中。但是它們的石化需要一系列因素：軟組織的腐爛速度緩慢，很少被其他動物殘食，缺少混雜、沖走小骨頭的快速水流和波浪，以及相當快地被掩埋。當這些因素存在時，某些地區(qū)就會變成一個充滿保存完好的魚龍化石的寶庫。
在德國獲爾茲梅登，那兒的.沉積物給人們提出了一個有趣的分析案例。人們在黑色的、含瀝青的海洋頁巖中發(fā)現(xiàn)了約19，000 年前沉積下來的 魚龍化石。幾年時間內(nèi)，在這些巖石中取得了數(shù)以千計的海洋爬行動物、魚類以及無脊椎動物的標本。它們的保存質(zhì)量非常的好，但更令人稱奇的是保存下來的育有胚胎的魚龍化石數(shù)目。
在獲爾茲梅登附近一個小地區(qū)的六個不同的頁巖層中分別發(fā)現(xiàn)了育有胚胎的魚龍化石。這表明大量的魚龍經(jīng)年累月重復(fù)使用一個特定的地點。那些胚胎已經(jīng)發(fā)育得相當完整了。比如，它們的蹼槳已經(jīng)完全形成了。有一個標本甚至被保存在產(chǎn)道中。而且，那塊頁巖包含著很多在20 到30 英寸之間的新生幼體的化石。
為什么在其他地方那么稀少的懷孕雌獸和幼體在獲爾茲梅登卻那么多呢? 因為其保存質(zhì)量幾乎舉世無雙，采集工作的進行一直是一絲不茍的。大家都認識到這些化石的價值極其珍貴，但這些因素并不能解釋這個有 趣的問題：為什么在一個特定的地點會如此集中地出現(xiàn)即將臨產(chǎn)的懷孕魚龍群呢?
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