Muchlessthanonepercentoftheearth'swatercanbeusedbyhumans．Areasthatneedalotofwateroftenhavetobringitinfromfaraway．Forexample，southernandcentralCaliforniagetmostoftheirwaterfromnorthernCalifornia．TheMidd

　　Muchlessthanonepercentoftheearth'swatercanbeusedbyhumans．Areasthatneedalotofwateroftenhavetobringitinfromfaraway．Forexample，southernandcentralCaliforniagetmostoftheirwaterfromnorthernCalifornia．TheMiddleEastandMexicoareamongtheplaceswherelargeareasareshortofwater．Muchoftheshortage（短缺）insuchplacesiscausedbypooruseofwater，suchaspollutionandwaste．

　　Mostplaceshaveenoughwaterfordrinking，farmingandindustries．However，ascitiesgrowlargerandindustriesexpand，moreandmorewaterisneeded．Thismaymeanthatmoresources（来源）ofwaterneedtobefound．Butbysavingwater，existing（现有的）watercanbeusedlonger．Thisallowstowns，citiesandindustriestogrowwithouttheneedtofindmorewatersources．

　　Whataresomewaysthatordinarypeoplecansavewater？

　　Asurveyshowsthatwashingclothes，takingshowersandusingtoiletsmakeupabout80percentofafamily'swaterusage．Sousingshowerheads，toilets，andtapsthatuselesswatercanhelpsavealotofwaterinthehome．

　　53．OneofthepossiblereasonswhyMiddleEastandMexicoareshortofwateris that___．

　　A．manyindustriesintheseplacesusealotofwater

　　B．theypolluteandwasteexistingwater

　　C．theyhavefewlakesandrivers

　　D．theydon'thaveenoughmoneytobuywater

　　54．What'sthemeaningoftheunderlinedword"expand"？___

　　A．发展 B．使用 C．浪费 D．匮乏

　　55．Accordingtothesurvey，whichprobablyusetheleastwaterinfamilies？___

　　A．Takingshowers．B．Usingtoilets．

　　C．Washingdishes．D．Washingclothes．

　　56．Whichofthefollowingcanwelearnfromthepassage？___

　　A．Bysavingwater，wemaynotneedtofindmorewatersources．

　　B．PeopleinsouthernandcentralCaliforniaarerich．

　　C．NorthernCaliforniawillnothaveenoughwaterinthefuture．

　　D．Washingclothesandwashingdishesmakeup40%ofafamily'swaterusage．