大学英语四级阅读理解试题及答案四（doc版）

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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,andtheinexperiencedgardenercanbeencouragedbythethoughtthatmoredamagere

2、sultsfromdoingitunnecessarilythanfromleavingthetreetogrowinitsownway.　　First,pruningmaybedonetomakesurethattreeshaveadesiredshapeorsize.Theobjectmaybetogetatreeoftherightheight,andatthesametimetohelpthegrowthofsmallsidebrancheswhichwillthickenitsappearanceorgiv

3、eitaspecialshape.Secondly,pruningmaybedonetomakethetreehealthier.Youmaycutdiseaedordeadwood,orbranchesthatarerubbingagainsteachotherandthuscausewounds.Thehealthofatreemaybeencouragedbyremovingbranchesthatareblockingupthecentreandsopreventingthefreemovementofair

4、.　　Oneresultofpruningisthatanopenwoundisleftonthetreeandthisprovidesaneasyentryfordisease,butitisawoundthatwillheal.Oftenthereisaracebetweenthehealingandthedeseaseastowhetherthetreewillliveordie,sothatthereisaperiodwhenthetreeisatrisk.Itshouldbetheaimofeverygar

5、denertoreducewhichhasbeenprunedsmoothandclean,forhealingwillbesloweddownbyroughness.Youshouldallowthecutsurfacetodryforafewhursandthenpaintitwithoneofthesubstancesavailablefromgardenshopsproducedespeciallyforthispurpose.Pruningisusuallywithoutinterferencefromth

6、eleavesandalsoitisveryunlikelythatthecutsyumakewillbleed.Ifthisdoeshappen,itis,ofcourse,impossibletopaintthemproperly.　　1.Pruningshouldbedoneto______.　　a.makethetreegrowtaller　　b.improvetheshapeofthetree　　c.getridofthesmallbranches　　d.makethesmallbranchesthicke

7、r　　2.Treesbecomeunhealthyifthegardener______.　　a.allowstoomanybranchestogrowinthemiddle　　b.doesnotprotectthemfromwind　　c.forcesthemtogrowtooquickly　　d.damagessomeofthesmallsidebranches　　3.Whyisaspecialsubstancepaintedonthetree?　　a.Tomakeawoundsmooth　　b.Topreven

8、tdiseaseenteringawound　　c.Tocoveraroughsurface　　d.Tohelpawoundtodry　　4.Agoodgardenerprunesatree______.　　a.atintervalsthroughouttheyear　　b.asquicklyaspossible　　c.occasionally