大学英语四级阅读理解试题与答案(四).doc

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1、......大学英语四级阅读理解试题及答案（四）十六　　Treesshouldonlybeprunedwhenthereisagoodandclearreasonfordoingsoand,fortunately,thenumberofsuchreasonsissmall.Pruninginvolvesthecuttingawayofobergrownandunwantedbranches,andtheinexperiencedgardenercanbeencouragedbythethoughtthatmoredamageresultsfromdoingitunnecessarily

2、thanfromleavingthetreetogrowinitsownway.　　First,pruningmaybedonetomakesurethattreeshaveadesiredshapeorsize.Theobjectmaybetogetatreeoftherightheight,andatthesametimetohelpthegrowthofsmallsidebrancheswhichwillthickenitsappearanceorgiveitaspecialshape.Secondly,pruningmaybedonetomakethetreehealthier

3、.Youmaycutdiseaedordeadwood,orbranchesthatarerubbingagainsteachotherandthuscausewounds.Thehealth.学习帮手.......ofatreemaybeencouragedbyremovingbranchesthatareblockingupthecentreandsopreventingthefreemovementofair.　　Oneresultofpruningisthatanopenwoundisleftonthetreeandthisprovidesaneasyentryfordisea

4、se,butitisawoundthatwillheal.Oftenthereisaracebetweenthehealingandthedeseaseastowhetherthetreewillliveordie,sothatthereisaperiodwhenthetreeisatrisk.Itshouldbetheaimofeverygardenertoreducewhichhasbeenprunedsmoothandclean,forhealingwillbesloweddownbyroughness.Youshouldallowthecutsurfacetodryforafe

5、whursandthenpaintitwithoneofthesubstancesavailablefromgardenshopsproducedespeciallyforthispurpose.Pruningisusuallywithoutinterferencefromtheleavesandalsoitisveryunlikelythatthecutsyumakewillbleed.Ifthisdoeshappen,itis,ofcourse,impossibletopaintthemproperly.　　1.Pruningshouldbedoneto______.　　a.mak

6、ethetreegrowtaller.学习帮手.......　　b.improvetheshapeofthetree　　c.getridofthesmallbranches　　d.makethesmallbranchesthicker　　2.Treesbecomeunhealthyifthegardener______.　　a.allowstoomanybranchestogrowinthemiddle　　b.doesnotprotectthemfromwind　　c.forcesthemtogrowtooquickly　　d.damagessomeofthesmallsidebran

7、ches　　3.Whyisaspecialsubstancepaintedonthetree?　　a.Tomakeawoundsmooth　　b.Topreventdiseaseenteringawound　　c.Tocoveraroughsurface　　d.Tohelpawoundtodry　　4.Agoodgardenerprunesatree______.　　a.atintervalsthroughouttheyear　　b.asqui