问题标题:
BItisnaturalthatchildrenarecuriousabouttheworldaroundthem.Forexample,theywanttoknowhowtheirheartsbeat.Theywanttoknowwhytheoceanwatertastessalty.Aschildrengrowup,theybecomecuriousaboutdifferentkindso
问题描述:

B

Itisnaturalthatchildrenarecuriousabouttheworldaroundthem.Forexample,theywanttoknowhowtheirheartsbeat.Theywanttoknowwhytheoceanwatertastessalty.

Aschildrengrowup,theybecomecuriousaboutdifferentkindsofthings.Whentheyarebabies,theyareinterestedinthepartsoftheirbodiesandinthesmilesoftheirmothers.Theybecomeinterestedinthephysicalworldaroundthem:theplants,theanimals,thesky.Later,theybecomeinterestedinthethingsthatpeoplehavemade:wheels,bicycles,cars.Andwhentheyareadults,theircuriositycontinues.Sometimesthiscuriosityleadstoacareer(生涯、职业)inscience.

Scientistsspendtheirlivestryingtofindoutabouttheworld.Thosewhoworkwiththeearthsciencesstudytheearth,theoceans,andtheskies.Otherscientistswhostudylivingthingsworkwiththebiologicalsciences.Athirdgroupofscientistsstudythephysicalsciences,e.g.physics,chemistry.

Thesescientistshavealreadydiscoveredalotaboutourworld.Forexample,theytelluswhyyourheartbeatsfastwhenyourun.Theysaythatwhenyouarequiet,yourheartnormallybeatssixty-fiveorseventy-fivetimesaminute.Yourheartisapump(泵)thatpumpsbloodtoallpartsofthebody.Thebloodcarriesoxygenandnutrition.Whenyourun,yourmusclesworkveryhardandusethenutritionthatthebloodcarriestothem.Themusclesneedoxygen,too.Soyourbrainsendsasignaltotheheart.Thesignalmeansthatthemusclesneedmorenutritionandoxygen.Thentheheartbeatsfastandsendsbloodquicklytothemuscles.Itmaybeat90to140timesaminute.

Ofcourse,scientistscannotanswerallofourquestions.Ifweask,“Whydoestheoceanwatertastesalty”scientistswillsaythatthesaltcomesfromrocks.Whenarockgetsveryhotorverycold,itcracks.Rainfallsintocracks.Therainthencarriesthesaltintotheearthandintotherivers.Theriverscarrythesaltintotheocean.Butthenweask,“Whathappenstothesaltintheocean?Theoceandoesnotgetsaltiereveryyear.”Scientistsarenotsureabouttheanswertothisquestion.

Weknowalotaboutourworld,buttherearestillmanyanswersthatwedonothave,andwearecurious.

45.Accordingtothepassage,whichofthefollowingstatementsistrue?

  A.Peop

冯元琨回答:
  45---48  DCAC    略
查看更多
闽ICP备2022014709号-7