英语翻译A glacier is a huge mass of ice that moves slowly over l

英语翻译
A glacier is a huge mass of ice that moves slowly over land.The term “glacier” comes from the French wordglace (glah-SAY),which means ice.Glaciers are often called “rivers of ice.”
Glaciers fall into two groups:alpine glaciers and ice sheets.
Alpine glaciers form on mountainsides and move downward through valleys.Sometimes,alpine glaciers create or deepen valleys by pushing dirt,soil,and other materials outof their way.Alpine glaciers are found in high mountains of every continent except Australia (althoughthere are many in New Zealand).The Gorner Glacier in Switzerland and theFurtwangler Glacier in Tanzania are both typical alpine glaciers.Alpineglaciers are also called valley glaciers or mountain glaciers.
Ice sheets,unlike alpine glaciers,are not limited to mountainous areas.Theyform broad domes and spread out from their centers in all directions.As ice sheetsspread,they cover everything around them with a thick blanket of ice,including valleys,plains,and even entire mountains.The largest ice sheets,called continental glaciers,spread over vast areas.Today,continental glacierscover most of Antarctica and the island of Greenland.
Massive ice sheets covered much of North America and Europe during the Pleistocene time period.This was the last glacial period,also known asthe Ice Age.Ice sheets reached their greatest size about 18,000 years ago.Asthe ancient glaciers spread,they carved and changed the Earth’s surface,creating many of the landscapes that exist today.During the Pleistocene IceAge,nearly one-third of the Earth’s land was covered by glaciers.Today,aboutone-tenth of the Earth’s land is covered by glacial ice.
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冰川是指陆地上缓慢移动的巨大冰块.”glacier”一词原指冰块,源于法语”glace”.因此,冰川也常被称为“冰之河”.
冰川分为两类：高山冰川和冰盖.
高山冰川形成于山腰,并沿山谷向下移动.有时,通过推开路径上的污物、土壤和其他物质,高山冰川也导致了山谷的形成或对该过程产生促进作用.几乎所有陆地上的高山地带都能发现高山冰川,但澳洲除外（虽然在新西兰存在许多此类冰川）.瑞士的Gorner冰川和坦桑尼亚的Furtwangler冰川都是典型的高山冰川.高山冰川也被称为山谷冰川或山丘冰川.
与高山冰川不同,冰盖并不限于山丘地带.它们形成于开阔穹地,从中心朝各个方向扩展,将周围所有物体都覆盖上一层厚厚的冰,包括山谷、平原,甚至整个山体.最大的冰盖称为大陆冰川,其覆盖面绵延数千里.如今,该冰川已覆盖大部分南极洲和格陵兰岛.
更新世时期,巨大的冰盖曾覆盖北美和欧洲的大部分地区.这是最近的冰川时期,也被称为冰河世纪.冰盖的覆盖面积在大约一万八千年前达到了最大.当古老冰川延伸时,它们雕刻并改变地表形貌,创造出许多当今景观.更新世冰河时期,近乎三分之一的地球表面被冰川覆盖.如今,这一覆盖面积已减少为大约十分之一.