大学英语四级阅读理解试题及答案四（word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,andtheinexperiencedgardenercanbeencouragedbythethoughtthatmoredamageresult

2、sfromdoingitunnecessarilythanfromleavingthetreetogrowinitsownway.　　First,pruningmaybedonetomakesurethattreeshaveadesiredshapeorsize.Theobjectmaybetogetatreeoftherightheight,andatthesametimetohelpthegrowthofsmallsidebrancheswhichwillthickenitsappearanceorgiveitaspec

3、ialshape.Secondly,pruningmaybedonetomakethetreehealthier.Youmaycutdiseaedordeadwood,orbranchesthatarerubbingagainsteachotherandthuscausewounds.Thehealthofatreemaybeencouragedbyremovingbranchesthatareblockingupthecentreandsopreventingthefreemovementofair.　　Oneresult

4、ofpruningisthatanopenwoundisleftonthetreeandthisprovidesaneasyentryfordisease,butitisawoundthatwillheal.Oftenthereisaracebetweenthehealingandthedeseaseastowhetherthetreewillliveordie,sothatthereisaperiodwhenthetreeisatrisk.Itshouldbetheaimofeverygardenertoreducewhi

5、chhasbeenprunedsmoothandclean,forhealingwillbesloweddownbyroughness.Youshouldallowthecutsurfacetodryforafewhursandthenpaintitwithoneofthesubstancesavailablefromgardenshopsproducedespeciallyforthispurpose.Pruningisusuallywithoutinterferencefromtheleavesandalsoitisve

6、ryunlikelythatthecutsyumakewillbleed.Ifthisdoeshappen,itis,ofcourse,impossibletopaintthemproperly.　　1.Pruningshouldbedoneto______.　　a.makethetreegrowtaller　　b.improvetheshapeofthetree　　c.getridofthesmallbranches　　d.makethesmallbranchesthicker　　2.Treesbecomeunhealth

7、yifthegardener______.　　a.allowstoomanybranchestogrowinthemiddle　　b.doesnotprotectthemfromwind　　c.forcesthemtogrowtooquickly　　d.damagessomeofthesmallsidebranches　　3.Whyisaspecialsubstancepaintedonthetree?　　a.Tomakeawoundsmooth　　b.Topreventdiseaseenteringawound　　c.To

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