（2020）新牛津译林版高中英语高一选择性必修第一册Unit 1 Grammar and usage ppt课件.rar

Step 1. To-infinitive as subjects 1.不定式直接作主语TospeakEnglishwellisntaneasyjob.Toimproveourteachingmethodisveryimportant.Totalkwithherisagreatpleasure.Step 1. To-infinitive as subjects 2.动词不定式短语作主语时，为了保持句子平衡，往往用it作形式主语，而把不定式短语置于谓语动词之后。如：TomasterEnglishgrammarisimportant.-ItisimportanttomasterEnglishgrammar.Step 1. To-infinitive as subjects 练习：用it做形式主语改写下面句子(1).TospeakEnglishwellisntaneasyjob.(2).Toimproveourteachingmethodisveryimportant.(3).Totalkwithherisagreatpleasure.(4).tolookupeverynewwordasitcomesalongwouldbeawasteoftime. It isnt an easy job to speak English. It is very important to improve our teaching method. It is a great pleasure to talk with her. It would be a waste of time to look up every new word as it comes along.Step 1. To-infinitive as subjects It+be+adj.+todosth.Itisimportanttobuildtrustbetweenemployersandemployees.Itisimportanttofinishwritingthebookintwoweeks.Itbeadj.forsbtodo（此处形容词常为描述事物特征的形容词，如easy、difficult、hard、importantimpossible、necessary等）ItwouldbedifficultforBobtofindagoodjob.ItisnecessaryforustobuyanEnglishdictionary.Itbeadj.ofsbtodo（此处形容词常为表示行为者的性格、品质等特点的词，如kind、foolish、good、nice、selfish、generous等）Itiskindofyoutogivemesomuchhelp.Itisfoolishofhimtorefusetheoffer.Step 1. To-infinitive as subjects Itben.todoItisourdutytoprotecttheenvironment.Itismyhonourtogiveaspeech.it动词宾语不定式Ittookmethreehourstocleantheroom.Itrequiresspecialskillstopreparethefood.itis+believed/reported/saidtodo=itbebelieved/reported/saidthat.itssaidtorainsoon (1).Itsbadforyoureyescomputergamestoomuch.A.playsB.toplayC.playD.playing(2).Thefluisbelieved_byvirusesthatliketoreproduceinthecellsinsidethehumannoseandthroat.A.causingB.beingcausedC.tobecausedD.tohavecaused B CStep2.To-infinitiveaspredicatives 某些系动词，如be（是）、seem（看起来）、appear（看起来）、prove（证明）、turnout（结果）等，后面可以接不定式作表语。其中，除了be动词之外，seem、appear、prove、turnout后面的表语若是以“tobe+.”的形式出现，通常可以省略tobe。Heseems（tobe）busy.Heappears（tobe）busy.他看起来很忙。Theplanproves（tobe）right.Theplanturnsout（tobe）right.这个计划证明是Step2.To-infinitiveaspredicatives 补充：需要注意的是，有些系动词，如sound（听起来）、smell（闻起来）、taste（尝起来）、feel（感觉）、become（成为）等，通常不可以接不定式作表语。练习：判断下列句子正误Itsmellstobedelicious.Thebookseemsavailable.Thecaketastestobeyummy. F T FStep3.To-infinitive的型式变化 1.To-infinitive否定形式是“notto动词原形”Theteacheraskedussomuchnoise.A.dontmakeB.notmakeC.notmakingD.nottomake DStep3.To-infinitive的型式变化 2.To-infinitive被动形式”Tobedone”Itwasagreathonourto(invite)heretoday.Thefestivalisto(hold)nextFriday.to be invitedto be heldStep3.To-infinitive的型式变化 3.单个不定式做主语，谓语动词用单数Toplaybasketball(be)great.如果and连接两个或更多并列的不定式作主语，谓语动词就用复数Toimprovepeopleslifeandtospeedupsocialistconstruction(be)ourtwoimportanttasks.isare