首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Standing on the rim of the Grand Canyon(大峡谷), gazing across this giant would in the Earth’s surface, a visitor might assume that
Standing on the rim of the Grand Canyon(大峡谷), gazing across this giant would in the Earth’s surface, a visitor might assume that
admin
2013-05-13
55
问题
Standing on the rim of the Grand Canyon(大峡谷), gazing across this giant would in the Earth’s surface, a visitor might assume that the canyon had been caused by some ancient convulsing (震动). In fact, the events that produced the canyon, far from being sudden and catastrophic, simply add up to the slow and orderly process of erosion.
Many millions of years ago, the Colorado Plateau in the Grand Canyon area contained 1000 more feet of rock than it does today and was relatively level. The additional material consisted of some 14 layered formations of rock. In the Grand Canyon region these layers were largely worn away over the course of millions of years.
Approximately 65 million years ago the plateau’s flat surface in the Grand Canyon area bulged upward from internal pressure, geologists refer to this bulging actions upwading(弯 曲上升); it was followed by a general elevation of the whole Colorado Plateau, a process that is still going on. As the plateau gradually rose, shallow rivers that winded across it began to run more swiftly and cut more definite courses. One of these rivers, located east of the upward, was the ancestor of the Colorado. Another river system, called the Hualapai, flowing west of the upward, extended itself eastward by cutting back into the upward, it eventually connected with the ancient Colorado and captured its waters. The new river then began to carve out the 277-mile-long trench that eventually became the Grand Canyon. Geologists estimate that this initial cutting action began no earlier than 10 million years ago.
Since then, the Canyon forming has been cumulative. To the corrosive force of the river itself have been added other factors. Heat and cold, rain and snow, along with the varying resistance of the rocks, increase the opportunities for erosions. the Canyon walls crumble, the river acquires a cutting tool. Tons of debris, rainfall running off the high plateau creates feeder streams that carve side canyons. Pushing slowly backward into the plateau, the side canyons expose new rocks, and the pattern of erosion continues.
It can be concluded from this passage about the Grand Canyon that______.
选项
A、its shapes are constantly changing
B、it contains approximately 14 million tons of rock
C、its eruptions have increased in recent years
D、it is being eroded by toxic waste and pollutants
答案
A
解析
最后一段“从那以后,大峡谷的形成日积月累,除了河流的侵蚀作用外,还有其他因素,如冷热、雨雪以及岩石的各种阻力增加了侵蚀的可能性。大峡谷壁面塌落,河流获得了切割工具。成吨的碎石和从高原上流下的雨水产生的支流切割峡谷壁,又逐步侵蚀到高原,峡谷边暴露出新的岩石,而侵蚀仍在继续”。可见应选[A]。
转载请注明原文地址:https://kaotiyun.com/show/FVjd777K
本试题收录于:
公共英语三级笔试题库公共英语(PETS)分类
0
公共英语三级笔试
公共英语(PETS)
相关试题推荐
Whatcanwelearnfromtheconversation?
ThefreeenterprisehasproducedatechnologycapableofprovidingtheAmericanconsumerwiththelargestandmostvariedmarket
Writeashortcompositionaboutthefollowingtopic.LivinginaBigCity
Evenplantscanrunafever,especiallywhenthey’reunderattackbyinsectsordisease.Butunlikehumans,plantscanhavethe
Writeashortcompositionaboutthefollowingtopic.Topic:HowdomoviesorTVinfluencepeople’sbehavior?Usereasonsand
Text…Themessageof【C1】______suchasthisis【C2】______naturalsystemsarecomplex,unpredictable:understandingthem【C3】
Text…Themessageof【C1】______suchasthisis【C2】______naturalsystemsarecomplex,unpredictable:understandingthem【C3】
Text…Themessageof【C1】______suchasthisis【C2】______naturalsystemsarecomplex,unpredictable:understandingthem【C3】
Supposeyoulostyoursuitcaseinbus.Accordingtotheinformationbelow,writeanessayofabout100wordstodescribeyourlo
Belowisagraphshowingthedistributionofcaraccidentsinacityduring2005.Lookatthegraphandwriteanessayofabout
随机试题
A.痰抗酸染色B.痰菌培养C.痰革兰染色D.痰真菌培养E.痰找阿米巴滋养体下列情况应进行何种检查肺部感染病原的快速判定
BNP/NT-proBNP主要用于诊断()
下列应计入产品成本的职工薪酬是()。
关于替代品的说法中,正确的有()
案例一般资料:求助者,女性,29岁,工人。案例介绍:求助者结婚两年,因工作关系一直两地分居。最近经常因小事与丈夫发生争执,目前处于“冷战”状态。求助者感觉非常苦恼,主动前来求助。下面是心理咨询师与求助者的一段咨询谈话。
阅读以下文字,完成问题。明代初期,因太祖朱元璋对南宋院体画风青睐有加,花鸟画大致延续了宋代院体工笔画风格,没有新突破。明宣宗朱瞻基同宋徽宗一样,雅好诗文书画,尤好花鸟画。他在位期间,宫廷画院的花鸟画风格面貌多样,有延续南宋院体花鸟画艳丽典雅风格的
设A为m×n矩阵,B为n×p矩阵,证明r(AB)≥r(A)+r(B)一n.
传国控制协议的英文缩写是()。
A、 B、 C、 C
Intheatmosphere,carbondioxideactsratherlikeaone-waymirror—theglassintheroofofagreenhousewhichallowsthesun’s
最新回复
(
0
)