2024剑桥雅思讲义Reading_Test_3.docx

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1、PaSSage1ClassesofTreesintheUSAThetimberoftheUnitedStatesisfurnishedbythreewell-definedclassesoftrees:(1)theneedle-leaved,naked-seededconifers,suchaspinezcedarzetc.,(2)thebroad-leavedtreessuchasoak,POPIai;etc.,and(3)toaninferiorextentbythe(one-seedleaf)palmszyuccas,andtheirallies,whichareconfinedtoth

2、emostsouthernpartsofthecountry.Broad-leavedtreesarealsoknownasdeciduoustrees,although,especiallyinwarmcountries,manyofthemareevergreen,whiletheneedle-leavedtrees(conifers)arecommonlytermedevergreens,althoughthelarch,baldcypress,andothersshedtheirleaveseveryfall,andeventhenamesbroad-leavedandconifero

3、us,thoughperhapsthemostsatisfactory,arenotatallexact,fortheconiferginkgohasbroadleavesandbearsnocones.Amongthewoodsmen,thewoodsofbroad-leavedtreesareknownashardwoods,thoughpoplarisassoftaspinezandtheconiferouswoodsareknownassoftwoods,notwithstandingthefactthatyewrankshighinhardnessevenwhencomparedwi

4、thhardwoods.Bothinthenumberofdifferentkindsoftreesorspeciesandstillmoreintheimportanceoftheirproducttheconifersandbroad-leavedtreesfarexcelthepalmsandtheirrelatives.Inthemanneroftheirgrowth,boththeconifersandbroad-leavedtreesbehavealike,addingeachyearanewlayerofwood,whichcoverstheoldwoodinallpartsof

5、thestemandlimbs.Thus,thetrunkcontinuestogrowinthicknessthroughoutthelifeofthetreebyadditions(annualrings),whichintemperateclimatesare,barringaccidents,accuraterecordsofthetreesage.Withthepalmsandtheirrelativesthestemremainsgenerallyofthesamediametecthetreeofahundredyearsoldbeingasthickasitwasattenye

6、arszthegrowthofthesebeingonlyatthetop.Evenwhereaperipheralincreasetakesplace,asintheyuccas,thewoodisnotlaidoninwell-definedlayersforthestructureremainsirregularthroughout.Thoughalikeinthemanneroftheirgrowth,andthereforesimilarintheirgeneralmake-up,conifersandbroad-leavedtreesdiffermarkedlyinthedetai

7、lsoftheirstructureandthecharacteroftheirwood.Thewoodofallconifersisverysimpleinitsstructure,thefibrescomposingthemainpartofthewoodallbeingalikeandtheirarrangementregular.Thewoodofthebroad-leavedtreesiscomplexinstructure;itismadeupofdifferentkindsofcellsandfibresandlackstheregularityofarrangementsono

8、ticeableintheconifers.Thisdifferenceissogreatthatinastudyofwoodstructureitisbesttoconsiderthetwokindsseparately.Inthiscountrythegreatvarietyofwoods,andespeciallyofusefulwoods,oftenmakesthemeredistinctionofthekindorspeciesoftreemostdifficult.Thus,thereareatleasteightpinesofthethirty-fivenativeonesont

9、hemarket,someofwhichsocloselyresembleeachotherintheirminutestructurethatonecanhardlytellthemapart,andyettheydifferinqualityandareoftenmixedorconfoundedinthetrade.Ofthethirty-sixoaks,ofwhichprobablynotlessthansixoreightaremarketed,wecanreadilyrecognizebymeansoftheirminuteanatomyatleasttwotribes-thewh

10、iteandblackoaks.Thesameistrueoftheelevenkindsofhickory,thesixkindsofashzandsoon.ThelistofnamesofalltreesindigenoustotheUnitedStates,asenumeratedbytheUnitedStatesForestService,is495innumber,thedesignationoftreebeingappliedtoallwoodyplantswhichproducenaturallyintheirnativehabitatonemain,erectstem,bear

11、ingadefinitecrown,nomatterwhatsizetheyattain.TimberisproducedonlybytheSpermatophyta,orseed-bearingplants,whicharesubdividedintotheGymnosperms(conifers),andAngiosperms(broad-leaved).Theconiferorcone-bearingtree,towhichbelongthepines,Iarcheszandfirs,isoneofthethreenaturalordersofGymnosperms.Thesearege

12、nerallyclassedassoftwoods,andaremoreextensivelyscatteredandmoregenerallyusedthananyotherclassoftimber,andaresimpleandregularinstructure.Theso-calledhardwoodsareDicotyledonsorbroad-leavedtrees,asubdivisionoftheAngiosperms.Theyaregenerallyofslowergrowth,andproducehardertimberthantheconifers,butnotnece

13、ssarilyso.Basswood,poplar;sycamorezandsomeofthegums,thoughclassedwiththehardwoods,arenotnearlyashardassomeofthepines.Source:https:WWW.autenberq.orci/files/26598/26598-h/26598-h.htm#SEenONIQuestions1-6Completethetablebelow.ChooseNOMORETHANONEAORDfromreadingpassage1foreachanswer.TreetypeAlsoknownasWoo

14、dknownasDiameterofthetrunkStructureofthewoodBroad-leaved13.Increasesin6Needle-IeavedConifersorConiferous5whilethetreeisSimple2woodsoralivePalms4.RemainsthesameAfteryou,vetriedthesequestions,checkyouranswerswiththefollowingvideo.Questions7-10CompleteeachsentencewiththecorrectendingA-Gfromtheboxbelow.

15、WritethecorrectletterA-Ginboxes7-10onyouranswersheet.NBnotallletterswillbeused.7. Despitethefactthatconifersareknownasevergreens,8. Somebroad-leavedtreeshave9. Intermsofthewoodproducedbythetree,thatofpalms10. SomegumtreesproducetimberA. moreringsthanconifers.B. ofgreatcomplexity.C. someofthemlosethe

16、irleavesintheautumn.D. thatissofterthanpine.E. isfarlessimportantthanthatofconifersandbroad-leavedtrees.F. thedifferenceinstructureisnegligible.G. woodthatisequalinsoftnesstopine.Afteryou,vetriedthesequestions,checkyouranswerswiththefollowingvideo.Questions11-14Completethesentencesbelow.ChooseNOMORETHANONEWORDfromthetextforeachanswer.