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1、ZQ国田IELTSADVANTAGEMatchingSentencesPaSSage1ClassesofTreesintheUSAThetimberoftheUnitedStatesisfurnishedbythreewell-definedclassesoftrees:(1)theneedle-leaved,naked-seededconifers,suchaspinezcedarzetc.,(2)thebroad-leavedtreessuchasoak,POPIai;etc.,and(3)toaninferiorextentbythe(one-seedleaf)palmszyuccas,
2、andtheirallies,whichareconfinedtothemostsouthernpartsofthecountry.Broad-leavedtreesarealsoknownasdeciduoustrees,although,especiallyinwarmcountries,manyofthemareevergreen,whiletheneedle-leavedtrees(conifers)arecommonlytermedevergreens,althoughthelarch,baldcypress,andothersshedtheirleaveseveryfall,and
3、eventhenamesbroad-leavedandconiferous,thoughperhapsthemostsatisfactory,arenotatallexact,fortheconiferginkgohasbroadleavesandbearsnocones.Amongthewoodsmen,thewoodsofbroad-leavedtreesareknownashardwoods,thoughpoplarisassoftaspinezandtheconiferouswoodsareknownassoftwoods,notwithstandingthefactthatyewra
4、nkshighinhardnessevenwhencomparedwithhardwoods.Bothinthenumberofdifferentkindsoftreesorspeciesandstillmoreintheimportanceoftheirproducttheconifersandbroad-leavedtreesfarexcelthepalmsandtheirrelatives.Inthemanneroftheirgrowth,boththeconifersandbroad-leavedtreesbehavealike,addingeachyearanewlayerofwoo
5、d,whichcoverstheoldwoodinallpartsofthestemandlimbs.Thus,thetrunkcontinuestogrowinthicknessthroughoutthelifeofthetreebyadditions(annualrings),whichintemperateclimatesare,barringaccidents,accuraterecordsofthetreesage.Withthepalmsandtheirrelativesthestemremainsgenerallyofthesamediametecthetreeofahundre
6、dyearsoldbeingasthickasitwasattenyearszthegrowthofthesebeingonlyatthetop.Evenwhereaperipheralincreasetakesplace,asintheyuccas,thewoodisnotlaidoninwell-definedlayersforthestructureremainsirregularthroughout.Thoughalikeinthemanneroftheirgrowth,andthereforesimilarintheirgeneralmake-up,conifersandbroad-
7、leavedtreesdiffermarkedlyinthedetailsoftheirstructureandthecharacteroftheirwood.Thewoodofallconifersisverysimpleinitsstructure,thefibrescomposingthemainpartofthewoodallbeingalikeandtheirarrangementregular.Thewoodofthebroad-leavedtreesiscomplexinstructure;itismadeupofdifferentkindsofcellsandfibresand
8、lackstheregularityofarrangementsonoticeableintheconifers.Thisdifferenceissogreatthatinastudyofwoodstructureitisbesttoconsiderthetwokindsseparately.Inthiscountrythegreatvarietyofwoods,andespeciallyofusefulwoods,oftenmakesthemeredistinctionofthekindorspeciesoftreemostdifficult.Thus,thereareatleasteigh
9、tpinesofthethirty-fivenativeonesonthemarket,someofwhichsocloselyresembleeachotherintheirminutestructurethatonecanhardlytellthemapart,andyettheydifferinqualityandareoftenmixedorconfoundedinthetrade.Ofthethirty-sixoaks,ofwhichprobablynotlessthansixoreightareQD国IELTSADVANTAGEMatching Sentencesmarketed,
10、wecanreadilyrecognizebymeansoftheirminuteanatomyatleasttwotribes-thewhiteandblackoaks.Thesameistrueoftheelevenkindsofhickory,thesixkindsofashzandsoon.ThelistofnamesofalltreesindigenoustotheUnitedStates,asenumeratedbytheUnitedStatesForestService,is495innumber,thedesignationoftreebeingappliedtoallwood
11、yplantswhichproducenaturallyintheirnativehabitatonemain,erectstem,bearingadefinitecrown,nomatterwhatsizetheyattain.TimberisproducedonlybytheSpermatophyta,orseed-bearingplants,whicharesubdividedintotheGymnosperms(conifers),andAngiosperms(broad-leaved).Theconiferorcone-bearingtree,towhichbelongthepine
12、s,Iarcheszandfirs,isoneofthethreenaturalordersofGymnosperms.Thesearegenerallyclassedassoftwoods,andaremoreextensivelyscatteredandmoregenerallyusedthananyotherclassoftimber,andaresimpleandregularinstructure.Theso-calledhardwoodsareDicotyledonsorbroad-leavedtrees,asubdivisionoftheAngiosperms.Theyarege
13、nerallyofslowergrowth,andproducehardertimberthantheconifers,butnotnecessarilyso.Basswood,poplar;sycamorezandsomeofthegums,thoughclassedwiththehardwoods,arenotnearlyashardassomeofthepines.Source:Sttos:WWW.a/tebeco.org/fi/es/26598/26598-/7/26598-/ibtm#SEC77ON/Questions7-10Completeeachsentencewiththeco
14、rrectendingA-Gfromtheboxbelow.WritethecorrectletterA-Ginboxes7-10onyouranswersheet.NBnotallletterswillbeused.7. Despitethefactthatconifersareknownasevergreens,8. Somebroad-leavedtreeshave9. Intermsofthewoodproducedbythetree,thatofpalms10. SomegumtreesproducetimberA. moreringsthanconifers.B. ofgreatcomplexity.C. someofthemlosetheirleavesintheautumn.D. thatissofterthanpine.E. isfarlessimportantthanthatofconifersandbroad-leavedtrees.F. thedifferenceinstructureisnegligible.G. woodthatisequalinsoftnesstopine.
