英语阅读题Intheevolutionofmammalsfromreptiles(爬行动物),therewasasuccessionofphysicalchanges:thedevelopmentofwarmblood,bodyhairinsteadofscales,andthebeginningofthenursingoftheyoung.Thisradicalphysicaltrans

　　英语阅读题

　　Intheevolutionofmammalsfromreptiles(爬行动物),therewasasuccessionofphysicalchanges:thedevelopmentofwarmblood,bodyhairinsteadofscales,andthebeginningofthenursingoftheyoung.Thisradicalphysicaltransformationprovidedmammalswithagreatertoleranceforexternaltemperatureandrequiredrelianceonspecializedfoodtypes.Whenthedominantdinosaurs（恐龙）becameextinct,theAgeofMammalsbegan.Fortherest60millionyearsmammalsexpandedintothebiologicalvacuumwhichtheywerebetterequippedtoexploitthanallbutafewvarietiesofreptiles.

　　Thehabitatoflifeformsonearthhasbeentheentireplanet,convenientlydividingtheworldintothebirdsoftheair,thefishofthesea,andthecreaturesoftheland.Theevolutionaryprocessalsocreatedsea-dwellingmammalswhoappearedtoreversetheprocessofevolutionastheyreturnedtothesea.Thewhales’limbsbecameflipperlike,andtheylostthehairontheirbodies,suitingthembettertoaquaticlife.

　　Ontheotherhand,inthecourseoftheevolutionofbirdsfromreptiles,therewasasuccessionofchangesinthebone,muscle,andskinstructuresoftheanimals.Thiswholesalerestructuringofsomereptilesoveraperiodofthousandsofyearsequippedthenewanimalstoescapetheirpredatorsandtofindfoodmoreeasily.Buttheevolutionaryprocessdidnotstopthere.Onceadaptedtoflight,somebirdscontinuedtochangeandtheprocessseemedtoreverseitself.Aspenguins（企鹅）adaptedtomarinelife,theirwingschangedtoflippersandtheirfeatherstoawaterproofcovering,thussuitingthebirdsforasemi-aquaticexistence.

　　1.TheAgeofMammalsbeganwhen____

　　A.animalsevolvedfromreptiles

　　B.animalsnursedtheyoung

　　C.animalsweremoretoleranttoexternaltemperature

　　D.thedominantdinosaursdiedout

　　2.Itcanbeconcludedfromthispassagethattheancestorsofwhales____

　　A.werefishB.chasedreptiles

　　C.livedonthelandD.hadtoomanyoffspring

　　3Inparagraph2,theword‘aquatic’isclosestinmeaningto____

　　A.ofearthB.ofland

　　C.ofriverD.ofwater

　　4.Certainreptilesgraduallybecameabletoescapequicklyby____.

　　A.acquiringnewstru