高三英语二轮复习-阅读理解科普知识型阅读理解课件.ppt

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1、科普知识型阅读理解专题导读专题八│专题导读科普类文章是高考阅读理解中的难点题材，其取材密切联系当前经济和科技等方面的变化，以介绍某一科学现象居多。科普类文章具有结构严谨、逻辑性强等特点。其主要命题形式有事实细节题、词义猜测题、推理判断题以及主旨概括题等，其中推理判断题居多。这类文章的总体特点是：科技词汇多，句子结构复杂，理论性强，逻辑严谨。具体说来它有以下特点：专题导读专题八│专题导读1．文章中词汇的意义比较单一、稳定、简明，不带感情色彩，具有单一性和准确性的特点。这类文章通常不会出现文学英语中常用的排比、比喻、夸张等修辞手法，一词多义的现象也不多见。2．句子结

2、构较复杂，语法分析较困难。为了描述一个客观事物，严密地表达自己的思想，作者经常会使用集多种语法现象于一体的长句。3．常使用被动语态，尤其是一些惯用被动句式。真题典例专题八│真题典例【2011·湖南卷】ArecentstudyofancientandmodernelephantshascomeupwiththeunexpectedconclusionthattheAfricanelephantisdividedintotwodistinct(不同的)species.ThediscoverywasmadebyresearchersatYorkandHarvardUn

3、iversitieswhentheywereexaminingthegeneticrelationshipbetweentheancientwoollymammothandmastodontomodernelephants—theAsianelephant，Africanforestelephant，andAfricansavannaelephant.OncetheyobtainedDNAsequences(序列)fromtwofossils(化石)，mammothsandmastodons，theteam专题八│真题典例comparedthemwithDNAf

4、rommodernelephants.TheyfoundtotheiramazementthatmodernforestandsavannaelephantsareasdistinctfromeachotherasAsianelephantsandmammoths.ThescientistsuseddetailedgeneticanalysistoprovethattheAfricansavannaelephantandtheAfricanforestelephanthavebeendistinctspeciesforseveralmillionyears.Th

5、edivergenceofthetwospeciestookplacearoundthetimeofthedivergenceofAsianelephantsandwoollymammoths.Thisresultamazedallthescientists.Therehaslongbeendebateinthescientificcommunitythatthetwomightbeseparatespecies，butthisisthemostconvincingscientificevidencesofarthattheyareindeeddifferent

6、species.专题八│真题典例Previously，manynaturalistsbelievedthatAfricansavannaelephantsandAfricanforestelephantsweretwopopulationsofthesamespecies，despitetheelephants’significantsizedifferences.Thesavannaelephanthasanaverageshoulderheightof3.5metreswhiletheforestelephanthasanaverageshoulderhei

7、ghtof2.5metres.Thesavannaelephantweighsbetweensixandseventons，roughlydoubletheweightoftheforestelephant.Butthefactthattheylooksodifferentdoesnotnecessarilymeantheyaredifferentspecies.HowevertheprooflayintheanalysisoftheDNA.AlfredRoca，assistantprofessorintheDepartmentofAnimalSciencesa

8、ttheUniversi