A.
Theworldisnothungry,butitisthirsty.Itseemsstrangethatnearly3/4oftheearthiscoveredwithwaterwhilewesayweareshortof(短缺)water.Why?Becauseabout97%ofwaterontheearthisseawaterwhichwecan'tdrinkoruseforwateringplantsdirectly(直接地).Mancanonlydrinkandusethe3%-thewaterthatcomesfromriversandlakes.Andwecan'tevenuseallofthat,becausesomeofithasbeenpolluted(污染).
Nowmorewaterisneeded.Theproblemis:Canweavoid(避免)aseriouswatershortagelateron?First,weshouldalllearnhowtosavewater.Secondly,weshouldfindoutthewaystoreuseit.Scientistshavealwaysbeenmakingstudiesinthefield.Today,inmostlargecitieswaterisusedonlyonceandthenrunstotheseaorrivers.Butitcanbeusedagain.Evenif(即使)everylargecityreuseditswater,stilltherewouldnotbeenough.Whatcouldpeopleturntonext?
Theseaseemstohavethebestanswer.Thereisalotofwaterinthesea.Allthatneedstobedoneistogetthesaltoutoftheseawater.Thisisexpensive,butit'salreadyusedinmanypartsoftheworld.Scientistsaretryingtofindacheaperwayofdoingit.Soyousee,ifwecanfindawayout,we'llbeinnodangerofdryingup.
1.Theworldisthirstybecause________.
A.3/4oftheearthiscoveredwithwater
B.wehaveenoughseawatertousedirectly
C.wehaven'tusedallthewaterinriversandlakes
D.about97%ofwaterontheearthcan'tbedrunkorusedforwateringplantsdirectly
2.Whichofthefollowingistrue?
A.3%ofwaterontheearthisinriversandlakes.
B.75%ofwaterontheearthisthesea.
C.97%oftheearthiscoveredwithwater.
D.3%ofwaterontheearthisseawater.
3.Fromthepassagewelearn_________.
A.ifeverycityreusesitswater,we'llbeinnodangerofdryingup
B.mancanonlydrinkanduseabout25%ofwaterontheearth
C.todayinmostlargecitieswaterisusedonlyonce
D.watercanbeusedonlyonce
答案DAC
