首页
登录
职称英语
The ocean bottom—a region nearly 2.5 times greater than the total land area
The ocean bottom—a region nearly 2.5 times greater than the total land area
游客
2025-01-23
15
管理
问题
The ocean bottom—a region nearly 2.5 times greater than the total land area of the Earth—is a vast frontier that even today is largely unexplored and uncharted. Until about a century ago, the deep-ocean floor was completely
inaccessible
, hidden beneath waters averaging over 3,600 meters deep. Totally without light and subjected to intense pressures hundreds of times greater than at the Earth’s surface, the deep-ocean bottom is a hostile environment to humans, in some ways as forbidding and remote as the void of
outer space
.
Although researchers have taken samples of deep-ocean rocks and sediments for over a century, the first detailed global investigation of the ocean bottom did not actually start until 1968, with the beginning of the National Science Foundation’s Deep Sea Drilling Project (DSDP). Using techniques first developed for the offshore oil and gas industry, the DSDP’s drill ship, the Glomar Challenger, was able to maintain a steady position on the ocean’s surface and drill in very deep waters,
extracting
samples of sediments and rock from the ocean floor.
The Glomar Challenger completed 96 voyages in a 15-year research program that ended in November 1983. During this time, the vessel logged 600,000 kilometers and took almost 20,000 core samples of seabed sediments and rocks at 624 drilling sites around the world. The Glomar Challenger’s core samples have allowed geologists to reconstruct what the planet looked like hundreds of millions of years ago and to calculate what it will probably look like millions of years in the future. Today, largely on the
strength
of evidence gathered during the Glomar Challenger’s voyages, nearly all earth scientists agree on the theories of plate tectonics and continental drift that explain many of the geological processes that shape the Earth.
The cores of sediment drilled by the Glomar Challenger have also yielded information critical to understanding the world’s past climates. Deep-ocean sediments provide a climatic record stretching back hundreds of millions of years, because
they
are largely isolated from the mechanical erosion and the intense chemical and biological activity that rapidly destroy much land-based evidence of past climates. This record has already provided insights into the patterns and causes of past climatic change—information that may be used to predict future climates. [br] The word "they" underlined in Paragraph 4 refers to ______.
选项
A、years
B、climates
C、sediments
D、cores
答案
C
解析
根据上下文,此处的they应是物质名词,因而应选C项。
转载请注明原文地址:https://tihaiku.com/zcyy/3925999.html
相关试题推荐
这种“自下而上”式的改革方式,力求进一步理顺中央和地方的金融管辖权,有效缓解中小企业融资难。This"bottomtotop"approachtof
Foralongtimeinthatvastregion,thislawwasinabeyance.A、activeuseB、dou
Theoceanbottom—aregionnearly2.5timesgreaterthanthetotallandarea
Theoceanbottom—aregionnearly2.5timesgreaterthanthetotallandarea
Theoceanbottom—aregionnearly2.5timesgreaterthanthetotallandarea
Theoceanbottom—aregionnearly2.5timesgreaterthanthetotallandarea
Theoceanbottom—aregionnearly2.5timesgreaterthanthetotallandarea
Theoceanbottom—aregionnearly2.5timesgreaterthanthetotallandarea
Theoceanbottom—aregionnearly2.5timesgreaterthanthetotallandarea
Theoceanbottom—aregionnearly2.5timesgreaterthanthetotallandarea
随机试题
Iwastakenbyafriendoneafternoontoatheatre.Whenthecurtainwasrai
Whenyoubuysomethingandpayforitwithbillsorcoins,youarepaying【B1
MemoTo:Peter,DeputyEditorFrom:DanielThoma
Indiaistofrugality(节俭)asBethlehemistoJesus.Asrichcountriesentera
Soabsorbedasishethatshedidnotdaretomakeasound.A、他那么聚精会神,她不敢说一句话。B、
Malelionsaxeratherreservedaboutexpendingtheirenergyinhunting.More
关于肾结核全肾切除的手术指征,下列选项不正确的是A.单侧肾结核肾实质破坏2/3以
显示屏花屏、黑屏、乱码等为一般缺陷。
下列哪个选项不属于红黏土的主要矿物成分?( )A.高岭石 B.伊利石 C.
人在每一瞬间,将心理活动选择了某些对象而忽略了另一些对象。这一特点指的是注意的(
最新回复
(
0
)