冰山(Icebergs)

师哈哈达人

　　icebergs are among nature＇s most spectacular creations, and yet most  people have never seen one. a vague air of mystery envelops them. they  come into being ----- somewhere ------in faraway, frigid waters, amid  thunderous noise and splashing turbulence, which in most cases no one  hears or sees. they exist only a short time and then slowly waste away  just as unnoticed.
　　objects of sheerest beauty they have been  called. appearing in an endless variety of shapes, they may be  dazzlingly white, or they may be glassy blue, green or purple, tinted  faintly of in darker hues. they are graceful, stately, inspiring -----  in calm, sunlight seas.but they are also called frightening and  dangerous, and that they are ---- in the night, in the fog, and in  storms. even in clear weather one is wise to stay a safe distance away  from them. most of their bulk is hidden below the water, so their  underwater parts may extend out far beyond the visible top. also, they  may roll over unexpectedly, churning the waters around them.
　　icebergs  are parts of glaciers that break off, drift into the water, float about  awhile, and finally melt. icebergs afloat today are made of snowflakes  that have fallen over long ages of time. they embody snows that drifted  down hundreds, or many thousands, or in some cases maybe a million  years ago. the snows fell in polar regions and on cold mountains, where  they melted only a little or not at all, and so collected to great  depths over the years and centuries.
　　as each year＇s snow  accumulation lay on the surface, evaporation and melting caused the  snowflakes slowly to lose their feathery points and become tiny grains  of ice. when new snow fell on top of the old, it too turned to icy  grains. so blankets of snow and ice grains mounted layer upon layer and  were of such great thickness that the weight of the upper layers  compressed the lower ones. with time and pressure from above, the many  small ice grains joined and changed to larger crystals, and eventually  the deeper crystals merged into a solid mass of ice.