资源描述:
《dogs and humans have been living side-by-side for about 15,000 years阅读理解答案》由会员上传分享,免费在线阅读,更多相关内容在应用文档-天天文库。
1、Dogsandhumanshavebeenlivingside-by-sideforabout15,000years阅读理解答案 Dogsandhumanshavebeenlivingside-by-sideforabout15,000years,buttherearetonsoffactsaboutdogsthatperhapswehaveneverheardof. Nightvision Dogshavegoodnightvision.Theirlargepupilsletmorelightinandtherods(视杆细胞)workb
2、etterinpoorlight.Butthebiggestfactoristhetapetum(反光组织),whichreflectlightatthebackoftheeye.Besides,dogs’whiskers(胡须)alsohelpthem“see”inthedarkbecausetheypickuponverysmallchangesinair,providingdogswithinformationaboutthesize,shape,andspeedofthingsnearby. Secrettailcode Dogsca
3、nusetheirtailstocommunicate.Theywagtheirtailstotherightwhentheyarerelaxedorhappy,andtotheleftwhennervousorthreatened.Whentheyreaggressive,thetailswillstickstraight-upintheair.Abroadwagisfriendlywhileaslowwagisneutral,neitherexcitednoranxious. Dreams Weoftenseeadog’sbodymaki
4、ngsuddenmovementsinitssleep.Dogshavethesamebrainwavepatternsashumans’whiletheyareasleep,sotheydreamjustlikewedo. Supernose Dogscanfindtheirwayhomedespitelongdistances.Theirnosesareavitalpartoftheirincrediblesenseofdirection.Thepartofadog’sbrainthatcontrolssmellis40timeslarg
5、erthanhumans’.They’reabletofollowsmellsformellsformiles.Furthermore,dogshaveanamazingabilitytorecognizethesmellsgivenoffbytheabnormalcellsinhumanbodies,includingcancer.Thisissomethingscientistsareeagertoexplorefurther.Andinteresting,adog’s“fingerprint”isonitsnose.Thepatternso
6、ndogs’nosesaresodistinctthattheycanactuallybeusedtoidentifytheanimals. Asixthsense Dogsactstrangelybeforesomethingbad,likeastormorearthquake,happens,fortheyaresensitivetolowfrequenciesthathumanscan’tsense.Sodon’tlettheirstrangebehaviorgounnoticednexttime.Itcouldsaveyourlife
7、. 28.Whichofthefollowingindirectlyhelpsdogsseewellinthedark? A.Theirrods.B.Theirtapetum.C.Theirwhiskers.D.Theirpupils. 29.Ifadogholdsupthetail,itindicates________. A.happinessB.attackC.friendlinessD.relaxation 30.Whathasn’tbeendiscoveredaboutadog? A.Whyitcansensenatural
8、disasters.B.Whyithasanacutesenseofsmell. C.Whatemotionsitshowswithi