首页
登录
职称英语
The Moon, which has undergone a distinct and complex geological history, pre
The Moon, which has undergone a distinct and complex geological history, pre
游客
2023-11-23
56
管理
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. [br] According to the passage lunar researchers have focused mostly on ______.
选项
A、the possibility of finding water on the Moon
B、the lunar regolith
C、cataloging various land formations
D、craters and their origins
答案
D
解析
细节理解题。由文章第二段最后一句话“Although various land forms were catalogued,the majority of astronomers attention was fixed on craters and their origins.”可知,“弹坑及其起源”是研究者主要关心的问题。
转载请注明原文地址:http://tihaiku.com/zcyy/3213042.html
相关试题推荐
Languageisfantasticallycomplex.Itsbuilt-inmeansofcombiningandrecom
Languageisfantasticallycomplex.Itsbuilt-inmeansofcombiningandrecom
Languageisfantasticallycomplex.Itsbuilt-inmeansofcombiningandrecom
Languageisfantasticallycomplex.Itsbuilt-inmeansofcombiningandrecom
Scientistsfindingoutthattheuniverseisevenlargerandmorecomplexthanan
FormostofAmericanhistory,businesseswereruntoprovidelivelihoodsan
FormostofAmericanhistory,businesseswereruntoprovidelivelihoodsan
FormostofAmericanhistory,businesseswereruntoprovidelivelihoodsan
FormostofAmericanhistory,businesseswereruntoprovidelivelihoodsan
FormostofAmericanhistory,businesseswereruntoprovidelivelihoodsan
随机试题
Tenminutes______tooshortatimetofinishthistest.A、isB、areC、hasD、haveA时
TheCommissionisexpectedtoproposeallowingpeopletochoosewhichlegal
A. B. C. D.
男性,73岁,4个月前心室前间壁心肌梗死,现病情稳定,生活能自理;1个月前胸部X
孕前期妇女除遵循喝一杯人群膳食指南外,应特别注意()A.每天足量饮水 B
染色体检查发现t(8;21),常见于A.ALL B.AML-M3 C.CMI
证券投资基金的市场营销在运用4Ps理论时,其特殊性不包括()。A.专业性 B
蝶腭动脉A.穿过棘孔的动脉分支是 B.穿过下颌孔的动脉分支是 C.穿过眶下孔
银行承兑汇票的承兑银行,应当按照票面金额向出票人收取()的手续费。A:千分之一
洋地黄中毒的最可靠的诊断是A.服用期间新出现各种心律失常,以异位快速心律失常伴传
最新回复
(
0
)