it作形式主语课件

为避免主语冗长,句子头重脚轻,经常用it作形式主语,主语从句放在后面作真正的主语。1.Itiscertainthathewillsucceed.2.Itisnotknownwhetherhewillgothere.3.Ithasnotbeendecidedyetwhenthey’llstarttheproject.“It”isusedasemptysubject.形式主语1.Itis＋名词＋从句Itisafactthat…事实是…Itisanhonorthat…非常荣幸Itiscommonknowledgethat…是常识能获邀参加你们的婚礼真是不胜荣幸风就是流动的空气,这是常识可惜他由于一个拼写错误没有得满分It’sagreathonorthatIhavebeeninvitedtoyourwedding.It’scommonknowledgethatwindismoving/flowingair.It’sapitythathedidn’tgetfullmarksbecauseofaspellingmistake.句型1.2.Itis+adj.+从句It’scertainthat…肯定…Itispossiblethat...很可能……Itisunlikelythat...不可能……Itisobviousthat…很明显…Itisnecessary\important\natural\...that…*_________________(很可能)shewillcomebacktomorrow.*_________________(很明显)thismeasureiseffective.+(should)+do…ItispossiblethatItisobviousthat句型2.另注意在主语从句中用来表示惊奇、不相信、惋惜、理应如此等语气时，谓语动词要用虚拟语气“(should)+do”，常用的句型有：Itisnecessary(important,natural,strange,etc.)that…Itissuggested(requested,proposed,desired,etc.)that…3.Ithappens(seems,looks,appears)that...该句型中it是形式主语，that引导的是主语从句,主句中的happen,seem等词是不及物动词．Ithappened(sohappened)thathemethisteacherinthestreet.碰巧Itseemsthathewillbebackinafewdays.句型3.Itseemsthatsb.do/bedoing/havedone/haddone=Sb.seemstodo/bedoing/havedone/tobedone/tohavebeenItseemedthathehadbeentoBeijingbefore.=HeseemedtohavebeentoBeijingbefore.It+不及物动词+从句Ithappenedthat...碰巧……Itoccurredtomethat…我突然想起…*________________(刚好)Icameintotheofficeatthattime.*____________________(我突然想起)Iforgettosenttheletter.IthappenedthatItoccurredtomethat句型4.据说他读过这篇小说.Itwassaidthathehadreadthisnovel.=Hewassaidtohavereadthisnovel.It+be+-ed分词+that-从句Itissaidthat……据说……Itisknownthat……据了解……Itisreportedthat……据报道……Itisbelievedthat……据认为……1.据说她两年前在美国留学It’ssaidthathestudiedinAmericatwoyearsago2.据说她现在正在美国留学It’ssaidthatheisnowstudyinginAmerica3.据说她现在懂三国外语It’ssaidthatheknowsthreeforeignlanguagesHeissaidtohavestudiedinAmericatwoyearsago.HeissaidtobestudyinginAmericanow.Heissaidtoknowthreeforeignlanguages.Itissuggested(ordered,required...)that...该句型和上一个同属一个句型。主句中的过去分词是表示请求，建议，命令等词时，that后的从句要用虚拟语气（should+动词原形），should可以省。常译为“据建议；有命令……）”。Itissuggestedthatthemeeting(should)beputoff.Itwasorderedthatwe(should)arrivethereintwohours.注意Itisdoubtfulwhethershewillbeabletocome她是否能来还不还说。Itwasclearenoughwhatshemeant.她的意思还不太清楚。Itwon’tmaketoomuchdifferencewhetherhewilljoinus.他是否参加我们队不会太重要。Hasitbeenfoundoutwhosettherecord?是谁破了纪录弄清楚了吗？5、可用whether和疑问词引导从句的有：Itisdoubtful(notknown,notdecided,notmadeclear,tobefoundout,beingconsidered,amystery,aquestion,+that/whether句型5Itisstillaquestionwhenweshallhaveoursportsmeeting.Itisamysterytomehowitallhappened.这事是怎么发生的还是个谜。Ithasn’tmadeclearwhenthenewroadistobeopenedtotraffic.新路什么时候通车还不清楚。6.Itdoesn’tmatterhow/whether(if)…结构中的主语从句不可提前。该句型中whether(if)引导的从句是真正主语，该句型常译为“不论（是否）……没关系……。Itdoesn'tmatteriftheyareold.Itdoesn’tmatterwhowillgoinsteadofme.谁代替我去不重要。句型6Itdoesn’tmatterwhetherheiswrongornot.(right)Whetherheiswrongornotdoesn’tmatter.(wrong)该句型是强调句型。被强调部分可以是主语，宾语，表语或状语。强调的主语如果是人，that可以由who换用。Itwasabout600yearsagothatthefirstclockwasmade.Itwastheythat(who)cleanedtheclassroomyesterday.ItwasinthestreetthatImetherfather.7.Itis+被强调部分+that...1.正确选用is或was.2.强调部分是人，可以用who.3.强调主语，that或who后面的谓语形式与主语一致．４．不能强调谓语．注意8.Itisnotuntil+被强调部分+that...该句型也是强调句型。主要用于强凋时间状语，译成汉语“直到……才……”，可以说是not...until...的强调形式。=ItwasnotuntilshetookoffherdarkglassesthatIrealizedshewasafamousfilmstar.Ididn'trealizeshewasafamousfilmstaruntilshetookoffherdarkglasses.=NotuntilshetookoffherdarkglassesdidIrealizeshewasafamousfilmstar.9.Itisthefirst(second…)timethat…该句型要和上一个句型区别开来。该句型中的that从句不用虚拟语气，而用完成时态。至于用什么完成时态，由主句的谓语动词的时态决定。如果是一般现在时，后面从句用现在完成时态；如果是一般过去时，后面从句则用过去完成时态。该结构中that可以省去；it有时用this替换，常译为“是第一（二）……次……”。It(This)isthefirsttimeIhavebeenhere.It(This)wasthefirsttimeIhadbeenhere.10.Itis…since...该句型主要用作处理瞬间动词的完成时，又要和表示一段时间的时间状语连用的问题。主句中是时间作表语，其时态是现在时或完成时，since引导的从句通常是一般过去时态，而且是瞬间动词。如果主句是一般过去时，从句则用过去完成时。Itis(hasbeen)5yearssincehisfatherdied.Itwas1949whenIwasborn.Itwasin1949thatIwasborn.区别句下面这个句子：11.Itis...when...该句型中的when引导的是一个时间状语从句，主句中的it指时间，表语由具体的时间充当。常译为“当……的时候，是……”。Itwas5o'clockwhenhecamehere.强调句型时间状语从句12.Itbe...before...该句型主句中的it指时间,主句中的时态常是一般将来时或过去时两种时态．主句中的表语多是long,notlong,3days,2weeks等表示时间段的词或短语。常译为“……之后……”。Itwas3daysbeforehewenttoBeijing.Itwillbenotlongbeforehefinisheshisjob.要过好几个月她才会适应这项工作．Itwillbemonthsbeforesheisfitforthejob.过了一星期他回来了．Itwasaweekbeforehecameback.过了不久，她认识到她错了．Itwasnotlongbeforesherealizedshewaswrong.他离开中国已经10年了．Itis10yearssinceheleftChina.如以过去某一时间为基点，则为：Itwas10yearssinceHehadleftChina.区别句意：ItisthreeyearssinceIlivedhere.ItisthreeyearssinceIhavelivedhere.ItisthreeyearssinceIbegantolivehere.我不住在这里已经有三年了。后两句的含义是：我住在这里已经有三年了。Itis+段时间+since.../Ithasbeen+段时间+since...表示“从……起已有多长时间了”。Itisthreeyearssincehesmoked.他不吸烟已有3年了。试比较：Itisthreeyearssincehebegantosmoke.Itisthreeyearssincehehassmoked.两句均意为：他吸烟已有3年了。用法：since从句中常用一般过去时，(1)若从句中是持续性动词的一般过去时，则表示该动作结束有多长时间了则翻译为“已经不再…多长时间了”；，(2)若是短暂性动词，的一般过去时，则表示该动作发生后，距离现在有多长时间了则翻译为“已经….多长时间了”(3)若是持续性动词的现在完成时，则表示动作和状态延续到现在(说话时刻)，其表示的时间的起点应从动作发生之时算起。注意：在这种结构中，since引导的从句绝对不能用否定式的谓语动词来表示否定意义。他好久没学汉语了。误：Itisalongtimesincehedidn’tstudyC