最新外研社五年级下册M3U2-Sam-ate-four-hamburgers.课件PPT.ppt 35页

'外研社五年级下册M3U2-Sam-ate-four-hamburgers. breadhotdogsausageshamburgersandwich复习fishmeatfishandchipseggscakesricenoodlesmilkjuice Ihadfor.eggsandmilkbreakfastbreakfastlunchdinnerIhadfor.sandwichesandchipslunchIhadfor.riceandmeatdinner复习Whatdidyouhavefor…? eatWords.ategivegavehavehaddrinkdrank eat–ateThemanateahamburgeryesterdaymorning. give-gaveThegirlgaveapresenttohergrandmayesterday. Readandlearn.DearDaming,TodaySamatefourhamburgersatschool!Helikeshamburgersverymuch.Linglinghadasandwichbecauseshedoesn’tlikehamburgers.ShegaveherhamburgerstoSam.ImissChinesefood.TonightMumisgoingtocookChinesefoodforus.LoveAmy在学校非常喜欢因为…把…给…为…烹饪…今晚、今夜 Listen,readandjudgeTorF.SamatefourhamburgersathometodayLinglinghadasandwichatschooltoday.3.Linglinglikeshamburgers.4.AmymissesChinesefood.FTFT Sam.Lingling.Yes,shedoes.Chinesefood.Amy. DearDaming，TodaySam______four____________atschool.He_____hamburgersverymuch.Linglinghada___________becauseshe_______likehamburgers.She____herhamburgerstoSam.I_____Chinesefood.TonightMumisgoingto______Chinesefoodforus.Love,AmyReadandAnswerlikesatehamburgerssandwichdoesn"tgavemisscook Exercises:Whatdidyoulastnight?(eat/ate)Imeatforlunchyesterday.(eat/ate)Whatdidhelastnight?(drink/drank)Hehamburgersverymuch.(like/likes)Mumisgoingtofishtonight.(cook/cooks)Ihavegot_____emailfromLingling.(an/a)Hegotanapple.(has/have)Imilklastnight.(drink/drank)eatatedrinklikescookanhasdrank -Whatdidyoueatlastnight?-Iate…cheesefishhamburgersnoodles -Whatdidyoudrinklastnight?-Idrank…waterteamilkjuice -Whatdidyoueat/drinklastnight?-Iate/drank…所有图片来自互联网。版权归原作者所有 Listenandsay.ea,eeteacherseeeaheadbreadearearhear[i:][e]/iə/ Listenandsay.earbearhearere,eirwheretheir[eə][eə] Trytoread.meetcleanbreaksweaternearyear 选出不同类的一项。()A.lunchB.gaveC.breakfast()A.fishB.meatC.cat()A.giveB.ateC.drank()A.cookB.noodlesC.miss()A.ateB.hadC.doesn’tBABCC 专题课堂(二)　全等三角形判定的综合应用第十二章　全等三角形 一、全等三角形判定方法的巧用类型：(1)已知两边对应相等，寻找第三边或夹角对应相等；(2)已知一边一角对应相等，寻找另一角或夹这一角的另一边对应相等；(3)已知两角对应相等，寻找任一边对应相等；(4)在直角三角形中，已知一条直角边(斜边)对应相等，寻找斜边(另一条直角边)对应相等． 【例1】如图，四边形ABCD的对角线AC与BD相交于点O，∠1＝∠2，∠3＝∠4.求证：(1)△ABC≌△ADC；(2)BO＝DO.分析：(1)已知∠1＝∠2，∠3＝∠4，寻找公共边AC，利用ASA可证明；(2)由(1)可得AB＝AD，利用SAS证△ABO≌△ADO可得．证明：(1)∵∠1＝∠2，AC＝AC，∠3＝∠4，∴△ABC≌△ADC(ASA)(2)∵△ABC≌△ADC，∴AB＝AD.又∵∠1＝∠2，AO＝AO，∴△ABO≌△ADO(SAS)，∴BO＝DO 【对应训练】1．如图，在四边形ABCD中，∠BAD＝∠BCD＝90°，BC＝DC，延长AD到E点，使DE＝AB.(1)求证：∠ABC＝∠EDC；(2)求证：△ABC≌△EDC. 2．如图，A，F，E，B四点共线，AC⊥CE，BD⊥DF，AE＝BF，AC＝BD.求证：△ACF≌△BDE. 3．如图，在△ABC与△DCB中，AC与BD交于点E，且∠BAC＝∠CDB，∠ACB＝∠DBC，分别延长BA与CD交于点F.求证：BF＝CF. 二、构造三角形证全等的常用方法类型：(1)倍长中线法：延长中线至一倍构造全等三角形，将有关的线段转化到一个三角形中去证明；(2)截长补短法：线段的和差问题常采用截长或补短法构造全等三角形，将转移的边、角和已知边、角有机地结合在一起；(3)补全图形法：此法可通过图形的平移、旋转或折叠实现；(4)作平行线构造三角形：可以将角进行转移，进而构造全等三角形；(5)根据角平分线构造全等三角形：已知角平分线，常直接利用角或边相等的关系构造三角形，也常过角平分线上的点向两边引垂线构造直角三角形而巧妙地解决问题． 【例2】如图，在△ABC中，∠ABC＝60°，AD，CE分别平分∠BAC，∠ACB，求证：AC＝AE＋CD.分析：在AC上截取AF＝AE，连接OF，由SAS证△AEO≌△AFO，得∠EOA＝∠FOA，从而得到∠DOC＝∠FOC＝60°，再由ASA证△COD≌△COF，得CD＝CF，从而得到结论． 【对应训练】4．如图，在△ABC中，AD是中线，已知AB＝5，AC＝3，求中线AD的取值范围． 5．如图，在△ABC中，BE是∠ABC的平分线，AD⊥BE，垂足为D.求证：∠2＝∠1＋∠C. 6．如图，已知∠AOB＝90°，OM是∠AOB的平分线，将三角尺的直角顶点P在射线OM上滑动，两直角边分别与OA，OB交于点C，D，证明：PC＝PD. 8．如图，在Rt△ABC中，∠ACB＝90°，AC＝BC，点D为BC的中点，CE⊥AD于点E，其延长线交AB于点F，连接DF.求证：∠ADC＝∠BDF.证明：过点B作BG∥AC交CF的延长线于点G，∴∠G＝∠ACE.∵AC⊥BC，CE⊥AD，∴∠ACE＋∠DCE＝∠ADC＋∠DCE＝90°，BG⊥BC，∴∠ACE＝∠ADC，∴∠G＝∠ADC.又∵AC＝CB，∠ACD＝∠CBG＝90°，∴△ADC≌△CGB(AAS)，∴BG＝CD＝BD.在等腰直角△ABC中，∠CAB＝∠ABC＝45°，∵BG∥AC，∴∠GBF＝∠CAB，∴∠GBF＝∠DBF，又∵BF＝BF，∴△GBF≌△DBF(SAS)，∴∠G＝∠BDF，∴∠ADC＝∠BDF'