Unit23telephones004127王冠清

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1、Unit23lesson90山东无棣一中王冠清0102030405060708091011121314yrNWSelf-introduction1.CanyoutellMyHobbiesfromthefollowingpictures?2.DoyouknowwhatIamdoingfromthesepictures?0102030405060708091011121314yrNW123456导入新课IntroductionCanyoutellmetheadvertisementsaboutthefoll

2、owingthing?0102030405060708091011121314yrNW123Unit23lesson900102030405060708091011121314yrNWListentothetextandAnswerthefollowingquestions:1.Howdoesatelephonework?1.work?Speakerphonethereceivingphonevoice(soundwave)→electricalsignals—apairoflines—electric

3、alsignals→soundwave0102030405060708091011121314yrNWQuestion23)Howtomakeacallwithahandletelephone?2)Howaboutthewires?1)Weretheearliesttelephonespopular?2.early┌→notpopular(tookalongtime)─buy,hire─heartelephone└→handletelephone→wind(electricity)→operator→c

4、onnect,noteYN0102030405060708091011121314yrNWReadParagraph3-5andanswerthefollowingquestions.Whenwasthefirsttelephonedirectoryprinted?Andhowmanytelephonesin1877andin1990?3.telephone┌①USA1878directory├②1877,2600└③1900,300million0102030405060708091011121314

5、yrNWQuestion3Question4What'sthedifferencebetweenelectricalsignalsandlightsignals?4.telephone—advances(electricalsignals↓——→lightsignals↓)equipmentweakerwithoutgettingweaker,clear)→insteadof…0102030405060708091011121314yrNWQuestion5.Canyoudescribethepartt

6、hatlightsignalsplayed?5.How?voice→electricalsignals→lightsignals→electricalsignals→sound0102030405060708091011121314yrNWLesson90TelephonesHowatelephoneworksisaquestionwhichnoteveryonecananswer.Whenyouspeakintothetelephone,thesoundwavesofyourvoiceareturne

7、dintoelectricalsignals.Thesignalissentdown apairofwirestothereceivingtelephone.Theretheelectricalsignalsischangedbackintosound.Theearliesttelephonewerenotpopularandittookalongtimebeforepeoplebegantohireorbuythem.Atthebeginningitwasdifficulttohearpeopleov

8、erlongdistances.Thewireswhichcarriesthetelephoneconversationswerethick,heavyandexpensive.Inthosedays,tomakeacall,youhadtowindahandleatthesideofyourphone.Thisproducedenoughelectricitytomakeyourcall.Youcalledtheoperatorandto