陳蕙雅思教材 - 雅思閱讀精選 (Icebergs)

Icebergs

Icebergs are amongnature's most spectacular creations, and yet most people

have never seen one. Avague air of        mystery envelops them.They come into

being -- somewhere -- infaraway, frigid waters, amid thunderous noise and        

splashing turbulence,which in most case no one hears or sees. They exist

only a short time andthen slowly waste  away just as unnoticed.

Objects of sheerestbeauty they have been called. Appearing in an endless

variety of shapes, theymay be dazzlingly white, or  they maybe  glassy

blue,  green or purple, tinted faintly or  in darker hues. They are

graceful, stately,       inspiring -- in calm, sunlight seas.

But they are also calledfrightening and dangerous, and that they are -- in

the night, in the fog,and in storms.         Even in clearweather one is wise to

stay a safe distance awayfrom them. Most of their bulk         ishidden below the

water, so theirunderwater parts may extend out far beyond the visible top.

          Also, they may roll over unexpectedly, churning the watersaround them.

Icebergs are parts ofglaciers that break off, drift into the water, float

about awhile, and finallymelt. Icebergs afloat today are made of

snowflakes that have fallenover long ages of time. They embody snows that  

drifted down hundreds, or  many thousands,  or in some cases maybe a

million years ago. Thesnows fell in polar regions and on      cold  mountains,

where they melted only alittle or not at all, and so collected to great

depths over the years and   centuries.

As each year's snowaccumulation lay on  the  surface, evaporation  and  

melting caused  the snowflakes slowly to lose their feathery points and

become tiny grains ofice. When new snow fell on top of the old, it too

turned to icy  grains. So blankets of snow and ice grainsmounted layer upon

layer and were of suchgreat thickness that the  weight of theupper layers

compressed the  lower ones. With time and  pressure from above, the many

small ice  grains     joinedand changed to larger crystals, and eventually the

deeper crystals mergedinto a solid mass of ice.

冰山 冰山是大自然最壯觀的創造之一，但大多數人卻從未看到過冰山，一種朦朧神秘的氣氛

籠罩著它們。  冰山形成於久遠的、寒冷的水體中，而且伴隨著雷聲轟鳴般的嘈雜和水花洶

湧的風暴，但卻無人耳聞目睹。冰山僅存在短短的一段時間就慢慢地悄無聲息地融化掉。冰 山具有最純粹的美，人們如是說。  

冰山呈現出千姿百態，可能白得耀眼，或者是閃耀著藍 色、綠色或紫色的玻璃般的光芒，或濃或淡。  它們在平靜的陽光照耀的海水中顯得優雅堂

皇，令人浮想聯翩。  但是人們亦把冰山稱為恐怖的和危險的。  它們的確如此--在夜間，霧 天和風暴肆虐時。

即便是在晴朗的天氣裡，與它們保持一段安全距離也是明智的。 冰山的 大部分體積穩藏于水下，因此其水下部分的伸展遠遠超過可見的頂部。  冰山也可能出人意

料地翻滾，劇烈地攪動周圍的水體。  冰山是冰川的一部分，從冰川斷裂漂流進水中，一段 時間後融化。  今天的冰山由多年前降落的雪花形成。  

它們的體內是數百年，或數千年，有 時甚至是數百萬年前的降雪。  這些雪花落在極地或寒冷的山上，僅有少量融化或根本不融

化，這樣經過許多年或許多世紀後積累了巨大的深度。  由於每年的雪花積累在表面之上， 蒸發和融化使得雪花慢慢失去其羽狀尖端而變成微小的冰粒。

當新的雪花降落到舊的表面 上，也變成了冰粒。  因而雪花覆蓋層和冰粒層層堆積起來直到如此之大的厚度以致較上層 的重量壓縮較下層。  

在時間和壓力的作用下，許多小冰粒結合到一起變成更大的晶體，最 終較底層的晶體合併成龐大而堅固的冰塊。