2024剑桥雅思讲义Matching_Sentences.docx
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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
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