Lesson 29 The hovercraft

Later it crossed the Channel, riding smoothly over the waves, which presented no problem.

后來氣墊船跨越英吉利海峽，平穩(wěn)地在波浪上方行駛，波浪不再產生阻力。

Lesson 29 The hovercraft

Since that time, various types of hovercraft have appeared and taken up regular service.

從那以后，各種各樣的氣墊船出現了，并開始了定期航行服務。

Lesson 29 The hovercraft

The hovercraft is particularly useful in large areas with poor communications such as Africa or Australia;

氣墊船在非洲、澳大利亞等交通不發(fā)達地區(qū)特別有用。

Lesson 29 The hovercraft

it can become a 'flying fruit-bowl', carrying bananas from the plantations to the ports;

它能成為飛行水果盤子，把香蕉從種植園運到港口。

Lesson 29 The hovercraft

giant hovercraft liners could span the Atlantic;

大型的氣墊班輪或許能跨越大西洋。

Lesson 29 The hovercraft

and the railway of the future may well be the 'hovertrain',

未來的火車或許能成為氣墊火車，

Lesson 29 The hovercraft

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.

靠氣墊在單軌上行駛而不接觸軌道，時速可達每小時300英里。氣墊船的前途是不可限量的。

Lesson 30 Exploring the sea-floor

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.

100年前，我們只知道海洋是二維平面形的，以及靠近陸地淺水區(qū)的深淺不一能給航行帶來危險。

Lesson 30 Exploring the sea-floor

The open sea was deep and mysterious,

無邊無際的海洋深邃而又神秘，

Lesson 30 Exploring the sea-floor

And anyone who gave more than a passing thought to the bottom confines of the oceans probably assumed that the sea bed was flat.

凡是稍稍想過大海海底的人大概都會認為海底是平坦的。

Lesson 30 Exploring the sea-floor

Sir James Clark Ross had obtained a sounding of over 2,400 fathoms in 1839,

在1839年，詹姆斯·克拉克·羅斯爵士曾測得海水深度超過2，400英尺；

Lesson 30 Exploring the sea-floor

but it was not until 1869,

但直到1869年，

Lesson 30 Exploring the sea-floor

when H.M.S. Porcupine was put at the disposal of the Royal Society for several cruises,

皇家學會用英國"豪豬號艦艇進行了幾次巡航后，

Lesson 30 Exploring the sea-floor

that a series of deep soundings was obtained in the Atlantic and the first samples were collected by dredging the bottom.

才在大西洋測得一個個海水深度，同時通過挖掘海底，取得了研究海底的首批樣品。

Lesson 30 Exploring the sea-floor

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.

此后不久，英國著名的“挑戰(zhàn)者”號艦艇對海底的那次考察，把對海床的研究確立為一個值得一流物理學家和地質學家從事的研究課題。

Lesson 30 Exploring the sea-floor

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 three miles deep,

海洋中很多地方可深達兩三英里，

Lesson 30 Exploring the sea-floor

and the existence of underwater features of considerable magnitude.

水下特征差異極大。

Lesson 30 Exploring the sea-floor

Today, enough soundings are available to enable a relief map of the Atlantic to be drawn

現在已有足夠的水深測量數據來繪制一張大西洋洋底地形圖，

Lesson 30 Exploring the sea-floor

and we know something of the great variety of the sea bed's topography.

而且我們對海底地形的千變萬化也有了一定的了解。

Lesson 30 Exploring the sea-floor

Since the sea covers the greater part of the earth's surface,

既然海洋覆蓋著地球的大部分表面，

Lesson 30 Exploring the sea-floor

it is quite reasonable to regard the sea floor as the basic form of the crust of the earth,

因此完全有理由把海床看作地殼的基本模殼，

Lesson 30 Exploring the sea-floor

with, superimposed upon, it the continents, together with the islands and other features of the oceans.

上面附加著大陸以及島嶼和海洋的其他形態(tài)。

Lesson 30 Exploring the sea-floor

The continents form rugged tablelands which stand nearly three miles above the floor of the open ocean.

大陸是崎嶇不平的高地，高出遼闊海洋海底近三英里。

Lesson 30 Exploring the sea-floor

From the shore line, out to a distance which may be anywhere from a few miles to a few hundred miles,

從海岸線向大海延伸幾英里到幾百英里的區(qū)域是大陸架慢坡，

Lesson 30 Exploring the sea-floor

runs the gentle slope of the continental shelf, geologically part of the continents.

從地質學上來說，它是大陸的一部分。

Lesson 30 Exploring the sea-floor

The real dividing line between continents and oceans occurs at the foot of a steeper slope.

大陸和海洋的真正分界線是在陡坡腳大陸架慢坡

Lesson 30 Exploring the sea-floor

This continental slope usually starts at a place somewhere near the 100-fathom mark

一般是從差不多100英尋水深的地方開始的，

Lesson 30 Exploring the sea-floor

and in the course of a few hundred miles reaches the true ocean floor at 2,500-3,500 fathoms.

一直延伸到幾百英里遠深達2，500至3，500的地方，

Lesson 30 Exploring the sea-floor

The slope averages about 1 in 30, but contains steep,

坡度平均約為1/30，但其中包括陡峭的，

Lesson 30 Exploring the sea-floor

probably vertical, cliffs, and gentle sediment-covered terraces,

乃至垂直的峭壁和沉積物覆蓋的緩和的階梯地帶，