首页
登录
职称英语
For all their great diversity of shapes and sizes, glaciers can be divided
For all their great diversity of shapes and sizes, glaciers can be divided
游客
2023-09-03
10
管理
问题
For all their great diversity of shapes and sizes, glaciers can be divided into two essential types: valley glaciers, which flow downhill from mountains and are shaped by the constraints of topography (地貌), and ice sheets, which flow outward in all directions from dome--like centers of accumulated ice to cover vast expanse of terrain. Whatever their type, most glaciers are remnants of great shrouds of ice that covered the earth years ago. In a few of these glaciers the oldest ice is very ancient indeed; the age of parts of the Antarctic sheet may exceed 500,000 years.
Glaciers are born in rocky womb above the snow line, where there is sufficient winter snowfall and summer cold for snow to survive the annual melting. The long gestation period of a glacier begins with the accumulation and gradual transformation of snow flakes. Soon after they reach the ground, complex snowflakes are reduced to compact, roughly spherical ice crystals, and the basic components of a glacier. As new layers of snow and firm, snow that survives the melting of the previous summer, accumulate, they squeeze out most of the air bubbles trapped within and between the crystals below. This process of recrystallization continues throughout the life of the glacier.
The length of time required for the creation of glacier ice depends mainly upon the temperature and the rate of snowfall. In Iceland, where snowfall is heavy and summer temperatures are high enough to produce plenty of melt--water, glacier ice may come into being in a relatively short time--say, ten years. In parts of Antarctica, where snowfall is scant and the ice remains well below its melting temperature year round, the process may require hundreds of years.
The ice does not become a glacier until it moves under its own weight, and it cannot move significantly until it reaches a critical thickness--the point at which the weight of the piled-up layers overcomes the internal strength of the ice and the friction between the ice and the ground. This critica} thickness is about 60 feet. The fastest moving glaciers have been gauged at not much more than two and a half miles per year, and some cover less than 1/100 inch in that same amount of time. But no matter how infinitesimal the flow, movement is what distinguishes a glacier from a mere mass of ice. [br] The author compares the formation of glaciers to______.
选项
A、the gradual transformation of snow flakes
B、the formation of crystals
C、the long gestation of a baby
D、the formation of air bubbles
答案
C
解析
根据题干关键词compares,the formation of glaciers定位到原文第二段。作者把冰川形成的地方比作是一个子宫,把冰川所需的形成过程比作孕育婴儿的过程。womb意为“子宫”。
转载请注明原文地址:https://www.tihaiku.com/zcyy/2982480.html
相关试题推荐
Thefoodwasdivided______accordingtotheageandsizeofthechildren.A、equa
Plato,anancientGreekphilosopher,believedthatmenaredividedintothre
Plato,anancientGreekphilosopher,believedthatmenaredividedintothre
Plato,anancientGreekphilosopher,believedthatmenaredividedintothre
Humanity’sprimal(原始的)effortstosystematizetheconceptsofsize,shapes,
Humanity’sprimal(原始的)effortstosystematizetheconceptsofsize,shapes,
Humanity’sprimal(原始的)effortstosystematizetheconceptsofsize,shapes,
Humanity’sprimal(原始的)effortstosystematizetheconceptsofsize,shapes,
Humanity’sprimal(原始的)effortstosystematizetheconceptsofsize,shapes,
Humanity’sprimal(原始的)effortstosystematizetheconceptsofsize,shapes,
随机试题
Non-VerbalCommunicationsAcrossCulturesNon-verbalcommunicationscanaffirm,
智能建筑的智能化意味着什么?
以下关于CPU与I/O设备交换数据时所用控制方式的叙述中,错误的是()A.程序
某建设工程设备购置费为500万元,基本预备费90万元,涨价预备费20万元,建筑安
ThenumberoftheUnitedStatescitizens
改善风湿病骨关节炎症状的首选药物是A.糖皮质激素 B.改善病情的抗风湿药 C
每个变电站抽查评价工作时间根据变电站规模不少于1至2周。
案例三: 一般资料:求助者,男性,43岁,公务员。 案例介绍:求助者的女儿今
生产、销售假药未对人体造成伤害的,可处A.拘役,并处罚金 B.3年以下有期徒刑
建设工程采用设计——施工总承包方式的不足是( )。A.工程质量控制难度大 B.
最新回复
(
0
)