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
63
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.
The passage mainly discusses______.
选项
A、patterns of erosion in different mountain ranges
B、forces that made the Grand Canyon
C、the increasing pollution of the Colorado River
D、the sudden appearance of the Grand Canyon
答案
B
解析
第一段指出大峡谷的形成是由于缓慢有序的侵蚀形成的;第二段又说几百万年前大峡谷一带还是平面的,后来被逐渐侵蚀;第三段说由于地面降起,便有了高原河流,也有了著名的大峡谷;最后一段又进一步说明了大峡谷的进一步形成是由于力的作用。因而本篇讨论的是形成大峡谷的各种力。故选[B]。
转载请注明原文地址:https://www.kaotiyun.com/show/HVjd777K
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
ThefreeenterprisehasproducedatechnologycapableofprovidingtheAmericanconsumerwiththelargestandmostvariedmarket
Oneofthebest-knownproverbsmustbe"earlytobed,earlytorise,makesamanhealthy,wealthy,andwise."Thepromisesofhe
Text…【C1】______Thanksgivingturkey,it’shardtofind【C2】______"American"food.TheUnitedStatesisalandof【C3】______
WisecompromiseisoneofthebasicprinciplesandvirtuesoftheBritish.Ifacontinentalgreengrocerasks14shillings(orc
Thefollowingfivetalksaredifferentopinionsaboutworkingathomeinsteadofworkinginofricesinthecentreoftowns.
Writeashortcompositionaboutthefollowingtopic.Topic:HowdomoviesorTVinfluencepeople’sbehavior?Usereasonsand
Forthefirsttimeinthescientificcommunity,thereistotalagreementthattheactivityofhumansisatleastpartlyresponsi
Text…Themessageof【C1】______suchasthisis【C2】______naturalsystemsarecomplex,unpredictable:understandingthem【C3】
Publicimage【C1】______tohowacompanyisviewedbyitscustomers,suppliers,andstock-holders,bythefinancialcommunity,by
随机试题
________,hedoesgetannoyedwithhersometimes.
《断魂枪》开头的社会环境描写,对后文人物性格展现的主要作用是【】
男性,40岁,曾为长途车司机,有野游史。近3年有静脉吸毒,因发热1月余、加重伴咳嗽、咳血痰2周收治。近年渐出现消瘦,体重下降10kg;近1月余出现不规则发热,以下午低热为多,有盗汗;近2周出现高热,渐出现咳嗽,咳血痰,经规律抗菌药物治疗无效。查体:T39.
与其他长期负债筹资相比,长期借款筹资的特点有()等。
下列各项中,属于《预算法》规定的地方各级政府财政部门的职权的有()。
下列说法正确的是()。
锄李锐拄着锄把出村的时候又有人问:“六安爷,又去百亩园呀?”倒拿着锄头的六安爷平静地笑笑:“是哩。”“咳呀。六安爷,后晌天气这么热,眼睛又不方便,快回家歇歇吧六安爷!”
某市为合理用电,鼓励各用户安装“峰谷”电表。该市原电价为每度0.53元,改装新电表后,每天晚上10点至次日早上8点为“低谷”,每度收取0.28元,其余时间为“高峰”,每度收取0.56元。为改装新电表每个用户须收取100元改装费。假定某用户每月用200度电,
红光为什么可以保护暗适应?
Thebookisdead.Technologyhaskilledit.Thelibrariesoftheworldaredoomingtobecomemuseums.Americans,however,【M1】___
最新回复
(
0
)