大学英语四级阅读理解试题与答案(四)

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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,andtheinexperiencedgardenercanbeencouragedbythethoughtthatmoredamageresultsfromdoingitun

2、necessarilythanfromleavingthetreetogrowinitsownway.　　First,pruningmaybedonetomakesurethattreeshaveadesiredshapeorsize.Theobjectmaybetogetatreeoftherightheight,andatthesametimetohelpthegrowthofsmallsidebrancheswhichwillthickenitsappearanceorgiveitaspecialshape.Secondly,pruningmayb

3、edonetomakethetreehealthier.Youmaycutdiseaedordeadwood,orbranchesthatarerubbingagainsteachotherandthuscausewounds.Thehealthofatreemaybeencouragedbyremovingbranchesthatareblockingupthecentreandsopreventingthefreemovementofair.....　　Oneresultofpruningisthatanopenwoundisleftonthetre

4、eandthisprovidesaneasyentryfordisease,butitisawoundthatwillheal.Oftenthereisaracebetweenthehealingandthedeseaseastowhetherthetreewillliveordie,sothatthereisaperiodwhenthetreeisatrisk.Itshouldbetheaimofeverygardenertoreducewhichhasbeenprunedsmoothandclean,forhealingwillbesloweddow

5、nbyroughness.Youshouldallowthecutsurfacetodryforafewhursandthenpaintitwithoneofthesubstancesavailablefromgardenshopsproducedespeciallyforthispurpose.Pruningisusuallywithoutinterferencefromtheleavesandalsoitisveryunlikelythatthecutsyumakewillbleed.Ifthisdoeshappen,itis,ofcourse,im

6、possibletopaintthemproperly.　　1.Pruningshouldbedoneto______.　　a.makethetreegrowtaller　　b.improvetheshapeofthetree　　c.getridofthesmallbranches　　d.makethesmallbranchesthicker　　2.Treesbecomeunhealthyifthegardener______.....　　a.allowstoomanybranchestogrowinthemiddle　　b.doesnotprotect

7、themfromwind　　c.forcesthemtogrowtooquickly　　d.damagessomeofthesmallsidebranches　　3.Whyisaspecialsubstancepaintedonthetree?　　a.Tomakeawoundsmooth　　b.Topreventdiseaseenteringawound　　c.Tocoveraroughsurface　　d.Tohelpawoundtodry　　4.Agoodgardenerprunesatree______.　　a.atintervalsthrough

8、outtheyear　　b.asquicklyaspossible　　c.occ