[简答]  二、阅读理解：阅读下面的短文，根据文章内容从A、B、C三个选项中选出一个最佳选项。WhenDr.RobertMetcalffirstusedasolarcooker,thefuturechangedformillionsofAfricans.Heknewthatbillionsofpoorpeoplearoundtheworlddependontheuseofwoodforcooking.Astheytakemoreandmorefirewoodfromwildareas.Theyaredestroyinghabitatsaroundtheworld.Woodcollectionisonereasonwhymanyanimalshavebecomeendangered.“Butsunshinecanbeanalternativetofire.” Dr.Metcalfsays.Sincehisfirstsolarcookedmeal,hehashelpedpeoplearoundtheworldtousesimplenewtechnologiestocooktheirfood.EachmorninginvillagesacrossEastAfrica,smallchildrenandtheirmotherswakeupandwalkseveralmilestocollectfirewoodtocooktheirfood.Ittakesmuchoftheday,andtheheavyfirewoodtheycarryhomeontheirheadslastsonlyafewdays.ThisiswhyDr.MetcalfspendseachsummerinAfrica.Heteacheswomenandchildreninvillageshowtocookwiththesun.Sofar,morethanthirtythousandAfricanfamiliesnowhavesolarcookers,and newprogramswillintroducesolarcookerstomillionsoffamilies.Tofindwater,womenandchildrenmayhavetowalklongdistancetodigholesindryriverbedsortogatherwaterfromstreamsandshallowwells.Theyfilltheirbuckets（桶）andcarrythemhomeontheirheads.Thebucketsoftenweighasmuchasfortypounds.Notonlyisfindingwaterhardwork,butthewaterisoftenpollutedwithgerms（细菌）thatmakepeoplesick.Dr.Metcalfandothersdevelopedasimple，reusabletoolthatpeoplecanusetomakesuretheirwaterissafetodrink．ThetooliscalkedaWAPI，whichstandsfor “WaterPasteurizationIndicator”.ThepasteurizationprocessisnamedafterLouisPasteur，whodevelopeditinthe1800s.1．WhydidMetcalfhelpAfricansusesolarcookers?A．Hewantedtohelpthemtofightpoverty．B．Hefounditadangerousjobtocollectfirewood．C．Herealizedusingfirewoodisnotgoodfortheenvironment．2．Theunderlinedword “it” inthethirdparagraphprobablyrefersto““．A．collectingfirewood                           B．cookingfoodC．cookingwiththesun                       3．EachsummerMetcalfstaysinAfricato ．A.doresearchonwaterB.takecareofsickpeopleC.spreadthetechniqueofusingsolarcookers4．WaterPasteurizationIndicatorwasdevelopedto ．A.killthebacteriainwaterB.honorLouisPasteurC.makewastewaterreusable 5．Itcanbeinferredfromtilepassagethat  ．A．AfricansfindithardtolearntousesolarcookersB．womenandchildreninAfricausuallyleadahardlifeC．thewaterAfricansdrinkisnotcleanthoughitiseasytoget