TheUNpassedaruleintheyear2004toimprovethequalityofdrinkwaterandreducedeathscausedbydrinkingunhealthywatereachyear.TheUNhasalreadyworkedoutthespecificplantoreducehalfofthenumberthatisfivethousand.TheUNannouncedintheworldthereareabout1/6oftheworldpopulationcan'tmeetthesanitationregulationofdrinkingwater.
Thewaterwedrinkanduseisrunningshortintheworld.Weallhavetolearntostopwastingourquitelimitedwater.Oneofthestepsweshouldtakeistofindwaysofreusingit.Experimentshavealreadybeendoneonthisfield.Todayinmostlargecitiesfreshwaterisusedonlyoncethenitrunsintowastesystem.Butitispossibletopipetheusedwatertoapurifying(净化)factory.Thereitcanbefiltered(过滤)andtreatedwithchemicalssothatitcanbeusedagainjustasitwerefreshfromaspring.Butevenlargecitiespurifiedandreuseditswaterwestillwouldnothaveenough.Thenwecouldturntotheoceans.Allwewouldhavetodotomakeuseofseawateronearthistogetthesaltoutofit.Thismethodhasalreadybeenusedinmanypartsoftheworld.
47.Thewaytostopwastingwateristo________.
A.doexperimentswithwater
B.purifytheusedwaterandreuseit
C.usefreshwateronceagain
D.makeuseofseawater
48.Thepassagetellsushowtoreusetheusedwater.Whichistherightorderoftheprocess?
a.tohavetheusedwaterfilteredb.toputchemicalinit
c.topipeittotheuser
d.topipetheusedwatertobepurifiedinafactory.
A.dabcB.bcdaC.bdcaD.dcba
49.Therewouldn'tbeenoughwaterforusifwedidn't________.
A.turntotheoceanformorewater
B.reuseusedwaterandmakeuseofseawater
C.makefreshwaterfromtheseawater
D.takestepstoreuseallwateronearth
50.Theword"it"underlinedinthelastparagraphrefersto________.
A.theprocessofcollectingsaltfromtheocean
B.theprocessofgettingridofthesaltinseawater
C.purifiedwater
D.seawater