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action depends on the surface； water or ground； over which it rides。
The first tests on the Solent in 1959 caused a sensation。 The hovercraft travelled first over the water； then mounted the beach； climbed up the dunes； and sat down on a road。 Later it crossed the Channel； riding smoothly over the waves； which presented no problem。
Since that time； various types of hovercraft have appeared and taken up regular service。 The hovercraft is particularly useful in large areas with poor munications such as Africa or Australia； it can bee a 'flying fruit…bowl'； carrying bananas from the plantations to the ports； giant hovercraft liners could span the Atlantic； and the railway of the future may well be the 'hovertrain'； riding on its air cushion over a single rail； which it never touches； at speeds up to 300 m。p。h。 the possibilities appear unlimited。
EGON LARSEN The Pegasus Book of Inventors
New words and expressions 生词和短语
hovercraft
n。 气垫船
Norfolk Broads
n。 诺福克郡的湖泊地区
cushion
n。 座垫
ring
v。 围
Solent
n。 （英国的）苏伦特海峡
sensation
n。 轰动
dune
n。 沙丘
plantation
n。 种植园
hovertrain
n。 气垫火车
参考译文
本世纪已研制出许多新奇的交通工具，其中最新奇的要数气垫船了。1953年，有一位50多岁名叫克里斯托弗。科克雷的原电子工程师，改行在诺福克郡的湖泊地区从事造船业，他向英国政府和工业界提出了他研究多年的一项计划。他的设想是：用一个低压空气或软垫来支撑船体，软垫周围用高压空气环绕。自那以后，人们很难决定是否应该将这种运载工具列为轮船、飞机，或是陆上交通工具，因为它是介于船和飞机之间。作为一个船舶技师，科克雷尔在寻找解决波浪阻力的方法，因为波浪阻力浪费掉了船在水面行驶的大量动力，从而限制了船的速度。他的解决办法是把船体提离水面，让船在一个气垫上行驶，气垫只有一两英尺厚。船底装上大量环状喷气嘴以实现这一目的。这样，船就能飞了，但飞不高。它的飞行限决于它所悬浮的水面或地面。
1959年，在苏伦特海峡进行的首次试航引起了轰动，气垫船先是在水面上行驶，后又登上海岸，爬上沙丘，最后停在路上。后来气垫船跨越英吉利海峡，平衡地在波浪上方行驶，波浪不再产生阻力。
从那以后，各种各样的气垫船出现了，并开始了定期航行服务。气垫船在非洲、澳大利亚等交通不发达地区特别有用。它能成为“飞行水果盘子”，把香蕉从种植园动到港口。大型的气垫班轮或许能跨越大西洋。未来的火车或许能成为“气垫火车”，靠气垫在单轨上行驶而不接触轨道，时速可达每小时300英里。气垫船的前途是不可限量的。
Lesson 30
Exploring the sea…floor
海底勘探
First listen and then answer the following question。
听录音，然后回答以下问题。
How did people probably imagine the sea…floor before it was investigated？
Our knowledge of the oceans a hundred years ago was confined to the two…dimensional shape of the sea surface and the hazards of navigation presented by the irregularities in depth of the shallow water close to the land。 The open sea was deep and mysterious； and anyone who gave more than a passing thought to the bottom confines of the oceans probably assumed that the sea bad was flat。 Sir James Clark Ross had obtained a sounding of over 2；400 fathoms in 1839； but it was not until of deep soundings was obtained in the Atlantic and the first samples were collected by dredging the bottom。 Shortly after this the famous H。 M。 S。 Challenger expedition established the study of the sea…floor as a subject worthy of the most qualified physicists and geologists。 A burst of activity associated with the laying of submarine cables soon confirmed the challenger's observation that many parts of the ocean were two to there miles deep； and the existence of underwater features of considerable magnitude。
Today； enough soundings are available to enable a relief map of the Atlantic to be drawn and we know something of the great variety of the sea bed's topography。 Since the sea covers the greater part of the earth's surface； it is quite reasonable to regard the sea floor as the basic form of the crust of the earth； with； superimposed upon； it the continents； together with the islands and other features of the oceans。 The continents form rugged tablelands which stand nearly three miles above the floor of the open ocean。 From the shore line； out a distance which may be anywhere from a few miles to a few hundred miles； runs the gentle slope of the continental shelf； geologically part of the continents。 The real dividing line between continents and oceans occurs at the foot a steeper slope。
This continental slope usually starts at a place somewhere near the 100…fatheom mark and in the course of a few hundred miles reaches the true ocean floor at 2；500…3；500 fathoms。 The slope averages about 1 in 30。 but contains steep； probably vertical； cliffs； and gentle sediment…covered terraces； and near its lower reaches there is a long tailing…off which is almost certainly the result of material transported out to deep water after being eroded from the continental masses。
T。F。GASKELL Exploring the Sea…floor from Science Survey
New words and expressions 生词和短语
navigation
n。 航海
sounding
n。 水深度
fathom
n。 寻（1寻等于1。8米）
porcupine
n。 箭猪
dredge
v。 挖掘
expedition
n。 远征
physicist
n。 物理学家
magnitude
n。 很多
topography
n。 地形
crust
n。 地壳
rugged
adj。崎岖不平
tableland
n。 高地
sediment
n。 沉淀物
terrace
n。 阶地
erode
v。 侵蚀
参考译文
100年前，我们只知道海洋是二维平面形的，以及靠近陆地浅水区的深浅不一能给航行带来危险。无边无际的海洋深邃而又神秘，凡是稍稍想过大海海底的人大概都会认为海底是平坦的。1839年，詹姆斯。克拉克。罗斯爵士曾测得海水深度超过2，400英寻；但直到1869年，皇家学会用英国“豪猪”号舰艇进行了几次巡航后，才在大西洋测得一个海水深度，同时能过挖掘海底，取得了研究海底的首批样品。此后不久，英国著名的“挑战者”号舰艇对海底的那次考察，把对海床的研究确立为一个值得一流物理学家和地质学家从事的研究课题，铺设海底电缆的热潮很快证实了“挑战者”号的观察结果：海洋中很多地方可深达两三英里，水下特征差异极大。
现在已有足够的水深测量数据来绘制一张大西洋洋底地形图，而且我对海底地形的千变万化也有了一定的了解。既然海洋覆盖着地球的大部分表面，因此完全有理由把海床看作地壳的基本模壳，上面附加着大陆以及岛屿和海洋的其他形态。大陆是崎岖不平的高地，高出辽阔的海洋海底近三英里。从海岸线向大海延伸几英里到几百英里的区域是大陆架慢坡，从地质学上来说，它是大陆的一部分。大陆和海洋的真正分界线是在陡破脚下。
大陆架慢坡一般是从差不多100英寻水深的地方开始的，一直延伸到几百英里远深达2，500至3，500的地方，那里才是真正的海底。坡度平均约为1/30，但其中包括陡峭的、乃至垂直的峭壁和沉积物覆盖的缓和的阶梯地带，在这个地带的低处是很长的一段尾沙地段，基本上可以断定这个地段是大陆块体上侵蚀下来的物质被水冲到深水处形成的。
Lesson 31
The sculptor speaks
雕塑家的语言
First listen and then answer the following question。
听录音，然后回答以下问题。
What do you have to be able to do to appreciate sculpture？
Appreciation of sculpture depends upon the ability to respond to form in there dimension。 That is perhaps why sculpture has been described as the most difficult of all arts； certainly it is more difficult than the arts which involve appreciation of flat forms； shape in only two dimensions。 Many more people are 'form…blind' than co