(3)说明文·提纲挈领拎出主旨大意Theconnectionbetweenpeopleandplantshaslongbeenthesubjectofscientificresearch.Recentstudieshavefoundpositiveeffects①.AstudyconductedinYoungstown,Ohio,forexample,discoveredthatgreenerareasofthecityexperiencedlesscrime.Inanother,employeeswereshowntobe15%moreproductivewhentheirworkplacesweredecoratedwithhouseplants.TheengineersattheMassachusettsInstituteofTechnology(MIT)havetakenitastepfurther—changingtheactualcompositionofplantsinordertogetthemtoperformdiverse,evenunusualfunctions.Theseincludeplantsthathavesensorsprintedontotheirleavestoshowwhenthey’reshortofwaterandaplantthatcandetectharmfulchemicalsingroundwater.“We’rethinkingabouthowwecanengineerplantstoreplacefunctionsofthethingsthatweuseeveryday,②”explainedMichaelStrano,aprofessorofchemicalengineeringatMIT.Oneofhislatestprojectshasbeentomakeplantsglow(发光)inexperimentsusingsomecommonvegetables.②Strano’steamfoundthattheycouldcreateafaintlightforthree-and-a-halfhours.Thelight,aboutone-thousandthoftheamountneededtoreadby,isjustastart.Thetechnology,Stranosaid,couldonedaybeusedtolighttheroomsoreventoturntreesintoself-poweredstreetlamps.Inthefuture,theteamhopestodevelopaversionofthetechnologythatcanbesprayedontoplantleavesinaone-offtreatmentthatwouldlasttheplant’slifetime.Theengineersarealsotryingtodevelopanonandoff“switch”wheretheglowwouldfadewhenexposedtodaylight.②Lightingaccountsforabout7%ofthetotalelectricityconsumedintheUS.②Sincelightingisoftenfarremovedfromthepowersource(电源)—suchasthedistancefromapowerplanttostreetlampsonaremotehighway—alotofenergyislostduringtransmission(传输).Glowingplantscouldreducethisdistanceandthereforehelpsaveenergy.②【文体分析·技巧点拨】1.文体分析:(1)说明文类型:①事物说明文。说明事物的状态、性质和功能。②事理说明文。揭示问题的实质或阐明事理。(2)常见的说明方法:举例法、分类法、分析法、列数据、作比较、下定义、类比等。(3)说明文的顺序:时间顺序、空间顺序、逻辑顺序等。(4)考查内容:多为不熟悉的事物或事理,如高新科技、新发明新技术、动植物、科普自然知识、产品工艺的原理和人文地理等。2.解题技巧:说明文的考查角度灵活,主旨大意题是常考题型之一,分为段落大意题、文章大意题和标题归纳题三类。段落大意题可通过段落主题句确定,文章大意和文章标题可通过归纳各个段落的主题句得出。具体步骤如下:【文本解构·素养提升】lamps;replacefunctions;afaintlight;glowingplants;Stre