ScientistsinIsraelhavediscoveredanewwaytotestforwaterpollutionby“listening”towhattheplantsgrowinginwaterhavetosay.Byshiningalaserbeam(激光束)onthetinypiecesofalgaefloatinginthewater，theresearche

　　ScientistsinIsraelhavediscoveredanewwaytotestforwaterpollutionby“listening”towhattheplantsgrowinginwaterhavetosay.

　　Byshiningalaserbeam(激光束)onthetinypiecesofalgaefloatinginthewater，theresearcherssaidtheyhearsoundwavesthattellthemthetypeandamountofcontamination(致污物)inthewater.

　　“Itisaredlight，tellingusthatsomethingisbeginningtogowrongwiththequalityofwater，”saidZvyDubinsky，anaquaticbiologistatIsrael’sBarIlanUniversity.“Algaeisthefirstthingtobeaffectedbyachangeinwaterquality.”“Thesecret，”hesaid，“istomeasuretherateofphotosynthesis(光合作用)inthealgae，meaningtheplant’sabilitytotransformlightintoenergy.”Duringphotosynthesis，plantsalsoreleaseoxygenintotheair.

　　Dubinsky’stechniqueiseasytoperformbecauseoftheover­abundanceofalgaeintheplanet’swater.Mostoftheoxygenintheatmospherecomesfromalgae.Aprototypetesterthatoccupiesaboutonesquaremeterofalaboratorydesktop，shootsalaserbeamatwatersamplestostimulatephotosynthesisinthealgae.Butnotallofthelaser’sheatisused.Dependingontheconditionofthealgaeandtherateofphotosynthesis，someoftheheatisshotbackintothewater，creatingsoundwaves，Dubinskysaid.Withaspecialunderwatermicrophone，researchersareabletoanalyzethestrengthofthesoundwavesanddeterminethehealthofthealgaeandtheconditionofthesurroundingwater.

　　“Algaesufferingfromleadpoisoning，likewastedischargedfrombatteryandpaintmanufacturingplants，willproduceadifferentsoundthanthosesufferingfromlackofironorexposuretoothertoxins，”saidresearcherYuliaPinchasov.Shesaidthattestingalgaephotosynthesiscandeterminewaterqualitymoreaccuratelyandeasilythanlabor­intensivemethodsnowusedlikechemicalandradioactivecarbontesting.

　　小题1:Theunderlinedword“algae”inParagraph2probablyreferstoakindof________.A．instrumentB．plantC．woodD．pollutant小题2:Whyisthealgaetested?A．Becauseitfloatsonthewater.B．Becauseitcanhavephotosynthesis.C．Becauseitisthefirsttobepollu