高考英语阅读训练（050）Treesshouldonlybepruned(修剪)whenthereisagoodandclearreasonfordoingsoand,fortunately,thenumberofsuchreasonsissmall.Pruninginvolvesthecuttingawayofovergrownandunwantedbranches,andtheinexperiencedgardenercanbeencouragedbythethoughtthatmoredamageresultsfromdoingitunnecessarilythanfromleavingthetreetogrowinitsownway.First,pruningmaybedonetomakesurethattreeshaveadesiredshapeorsize.Theobjectmaybetogetatreeoftherightheight,andatthesametimetohelpthegrowthofsmallsidebrancheswhichwillthickenitsappearanceorgiveitaspecialshape.Secondly,pruningmaybedonetomakethetreehealthier.Youmaycuroutdiseasedordeadwood,orbranchesthatarerubbingagainsteachotherandthuscausingwounds.Thehealthofatreemaybeencouragedbyremovingthebranchesthatarelockingupthecentreandsopreventingthefreemovementofair.Oneresultofpruningisthatanopenwouldisleftonthetreeandthisprovidesaneasyentry(进入)fordiseases,butitisawoundthatwillheal.Oftenthereisaracebetweenthehealingandthediseaseastowhetherthetreewillliveordie,orthatthereisaperiodwhenthetreeisatrisk.Itshouldbetheaimofeverygardenertoreducetheriskasfaraspossible.Itisessentialtomaketheareawhichhasbeenprunedsmoothandclean,forhealingwillbesloweddownbyroughness.Youshouldallowthecutsurfacetodryforafewhoursandthenpaintitwithoneofthesubstancesavailablefromgardenshopsproducedespeciallyforthispurpose.Pruningisusuallydoneinwinter,forthenyoucanseetheshapeofthetreeclearlywithouttheinterference(干扰)fromtheleavesanditis,too,veryunlikelythatthecutsyoumakewillbleed.Ifthisdoeshappen,itis,ofcourse,impossibletopaintthemproperly.1.Accordingtothearticle,_____.A.damageisdonetoatreeifitislefttogrowinitsownwayB.pruningisnecessarywhenatreehasgrownintoadefiniteshapeorsizeC.diseasedordeadbranchesshouldbecutawayiftheyarefoundtorubagainsteachotherD.growingsidebranchesoftenpreventairfrommovingfreely2.Whichofthefollowingusuallycausesatreetogrowunhealthy?A.GivingatreeaspecialshapeandadefiniteheightB.Removingsmallsidebranchesandmakingatreelooklessth