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
The Moon, which has undergone a distinct and complex geological history, presents a striking appearance. The moon may be divided
The Moon, which has undergone a distinct and complex geological history, presents a striking appearance. The moon may be divided
admin
2009-01-05
55
问题
The Moon, which has undergone a distinct and complex geological history, presents a striking appearance. The moon may be divided into two major terrains: the maria (dark lowlands) and the terrace (bright high lands). The contrast in the reflectivity (the capability of reflecting light) of these two terrains suggested to many early observers that the two terrains might have different compositions, and this supposition was con firmed by missions to the Moon such as Surveyor and Apollo. One of the most obvious differences between the terrains is the smoothness of the maria in contrast to the roughness of the highlands. This roughness is mostly caused by the abundance of craters; the highlands are completely covered by large craters (greater than 40- 50km in diameter), while the craters of the maria tend to be much smaller. It is now known that the vast majority of the Moon’s craters Were formed by the impact of solid bodies with the lunar surface.
Most of the near side of the Moon was thoroughly mapped and studied from telescopic pictures years before the age of space exploration. Earth-based telescopes can resolve objects as small as a few hundred meters on the lunar surface. Close observation of craters, combined with the way the Moon diffusely reflects sunlight, led to the understanding that the Moon is covered by a surface layer, or regolith, that overlies the solid rock of the Moon. Telescopic images permitted the cataloging of a bewildering array of land forms. Craters were studied for clues to their origin; the large circular maria were mapper. Wispy marks on the surface (known as rays) emanating from certain craters were seen. Strange, sinuous features were observed in the maria. Although various land forms were catalogued, the majority of astronomers’ attention was fixed on craters and their origins.
Astronomers have known for a fairly long time that the shape of craters changes as they increase in size. Small craters with diameters of less than 10-15km have relatively simple shapes. They have rim crests that are elevated above the surrounding terrain, smooth, howl-shaped interiors, and depths that are about one-fifth to one-sixth their diameters. The complexity of shape increases for larger craters.
What does the passage mainly discuss?
选项
A、What astronomers learned from the Surveyor and Apollo space missions.
B、Characteristics of the major terrains of the Moon.
C、The origin of the Moon’s craters.
D、Techniques used to catalogue the Moon’s land forms.
答案
B
解析
主旨判断题。综观全文可知,文章主要解释月球地形形成的特点。因此,B为正确答案。
转载请注明原文地址:https://kaotiyun.com/show/1SBK777K
0
专业英语四级
相关试题推荐
Morethan2,000yearsago,thephilosopherSocrateswanderedaroundAthensaskingquestions,anapproachtofind【M1】______truth
Itisconvenienttodistinguishbetweennonverbalandverbalcommunication,justasistodistinguishbetweendecodingand【M1】__
Zoologicalparksinmanycitiesexportbirdsfrommanylandsandareasourceofrecreationformillionsofpeopleeachyear.
Kissing,strokingandwildembracesarecommonenough,andnowthequiet,romanticgestureofholdinghandsinpublicisa【M1】__
Kissing,strokingandwildembracesarecommonenough,andnowthequiet,romanticgestureofholdinghandsinpublicisa【M1】__
Stoppingcigarettesmokinghasbecomeabigproblemforallgovernments.Indemocraticcountries,theeconomicstrengthofthe
ComputerCrimeI.IntroductionCurrentsituation:theincreaseinthenumberandtypesofcomputercrimeII.【T1】______
MakeThataDoubleAfewyearsago,itdawnedonZachThomasthatcoffeedidn’thaveenoughcaffeine.Atthetime,hewaspul
Foodisirradiated(用辐射处理)toprovidethesamebenefitsaswhenitisprocessedbyheat,refrigeration,freezingortreatedwit
随机试题
斜Y坡口焊接裂纹试验时,焊后试件需放置()后,才能做裂纹检验。
肋膈隐窝()
普济消毒饮中配伍升麻、柴胡的用意是
2003年1月9日,某县人民检察院以贪污、受贿嫌疑将某国有企业总经理乔某逮捕,后向县人民法院提起公诉。8月16日,县人民法院作出一审判决。以贪污罪、受贿罪数罪井罚,判决乔某有期徒刑8年。乔某不服,上诉至市中级人民法院。市中级人民法院经审理维持原判.并将乔某
租售期延长会增加房地产开发项目的融资成本和管理费用等项支出,特别是在贷款利率较高的情况下,会给开发商带来沉重的财务负担。()
由建设单位主持,检查施工合同的执行情况,评价工程质量是否符合技术标准及设计要求,是否可以移交下一阶段施工称为()。
土方工程施工定位桩采用( )进行检查。
领导让你负责一项工作。需要其他两个部门的配合。但是这两个部门和你所在部门关系不太融洽。你怎么处理?
1,2,7,2,5,16,2,3,( )
函数z=x2+y2在条件=1下的极值为().
最新回复
(
0
)