资源描述：
《2019-2020年高三下学期周练（1）英语试题 含答案》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。
1、2019-2020年高三下学期周练（1）英语试题含答案一、阅读理解Ifyoulookatthenightsky,you’lloftenseestarsmovingveryquickly.Infact,theymovemuchmorequicklythantheyshouldaccordingtotheirsizeandthelawsofphysics.Scientistsdonotpletelyunderstandwhythespeedofthesestarsissohigh.Butmanybelievethereasonisthatmuchoftheuniverseismad
2、eofsomethingcalled“darkmatter”.Groupsofstarscalledgalaxies,suchastheMilkyWay,mightevenbemadeupof90percentdarkmatter.Howmuchsomethingweighsdependsonwhereitis.ThesameobjectweighsonlyhalfasmuchonMarsasitdoesonEarthandalmostthreetimesasmuchonJupiter.Soscientistsprefertotalkaboutthemass(质量)ofsome
3、thingratherthanhowmuchitweighs,becausemassdoesnotchange.Theycanworkoutthemassofgalaxiesbymeasuringthedistancebetweenthemandthespeedtheymoveat.Recently,JorgePeñarrubia,asenioracademicatEdinburghUniversity,UK,andhisteamdiscoveredsomethinginteresting:ThemassoftheMilkyWayisonlyhalfasmuchasthemas
4、sofanothernearbygalaxy,Andromeda.Thisseemsstrange,anddarkmattermayexplainwhy.Findingoutmoreaboutdarkmattercouldhelpusunderstandhowtheuniversebegan,butthisisnoteasy.Lotsofscientistswithdifferenttypesofexpertknowledgeareworkingontheproblem.Wecan’tseedarkmatter,it’sverydifficulttomeasureandweca
5、n’tfindoutitsmass.Unlikestars,darkmatterdoesn’tproduceorreflectlight.Butwecanmakeagoodguessthatitistherebecauseofthewaythingsmoveandthewaylightbends.ExpertsnowthinkdarkmattermaybeverydifferentfromthematterthatwefindonEarth.Theremayalsobefivetimesasmuchdarkmatterintheuniverseasordinarymatter.
6、1．Somethingthatweighs15kgonEarthweighsabout_____onMarsand_____onJupiter.A.7.5kg,45kgB.30kg,45kgC.45kg,7.5kgD.5kg,30kg2．TheauthormentionsthemassesoftheMilkyWayandAndromedamainlyto_____.A.explainwhythesameobjecthasadifferentweightondifferentstarsB.parethedistancebetweentheMilkyWayandAndromedaC
7、.showthatstudyingdarkmattercouldhelptoanswersomescientificquestionsD.supporttheideathatscientistsprefertotalkaboutmassinsteadofweight3．Darkmatterisdifficulttoinvestigatebecause_____.A.ittravelsataveryfastspeedB.wecan’tseewhereitisormeasureitsmassC.
