英语中it用法ppt课件

it用法 it用作主语 it指代事物 动物 婴儿或未知的人Whatisthis Itisabook Someoneisatthedoor Whoisit Hernewbabyistiny Itonlyweighs2kilos 指代天气 时间 距离 季节 事物的状态和自然环境等Itisgettingcolderandcolder ItistwoyearssinceIlastsawyou Itwasveryquietinthecafe HowisitwithMr Rose Itisonlytwentyminutes drivetoourcollege it作形式主语 代替不定式 动名词或从句 使原来的这些主语可以放在句子后面 避免句子头重脚轻 1 it代替不定式作主语Itcostme 25tobuythedictionary IsitnecessarytocompletethedesignbeforeNationalDay It sagoodideatohavealittlenotebookhandby 注意 有时不定式前面有一个for引起的短语 表示不定式逻辑上的主语 用it作形式主语时 构成下面句型Itis adj forsb todo此句型中的形容词为静态形容词 即描写人或物的静态特征的形容词 用来表示客观情况 这样形容词有 easy difficult important hard necessary essencial impossible dangerous common unusual big small tall long short wide old young beautiful等 ItisverydifficutformetolearnSpanish Itisgettinghardereverydayforapoormantogetaliving 注意 有时不定式前面有一个of引起的短语 表示不定式逻辑上的主语 用it作形式主语时 构成下面句型 Itis adj ofsb todo此句型中的形容词为动态形容词 即指那些有动作含义的词 或为描写人或物的特征或品质的形容词 这样的形容词有 bold brave busy careful careless clever considerate cruel foolish friendly generous good honest kind lazy nice noisy polite rude reasonable selfish shy silly stupid thoughtful wicked等Itwasgenerousofyoutocontributesomuch Itwascarelessofhertoloseherkeyofthesafe 2 it代替动名词作形式主语 而作主语的动名词常放在表语后 在此句型中的表语有下列名词和形容词 nogood nouse awasteoftime fun hardwork pity awonder dangerous difficult senseless useless foolish nice hard interesting worth worthwhile terrible tiring funny It snousestudyingforanexamatthelastminute Itisdifficultfindingyourwayaroundhere 3 it代替从句作主语 有以下四个常见句型1 It be adj that从句这样的adj通常有 possible probable likely很可能impossible unlikely不可能obvious显而易见certain很肯定 plain很明显true真的clear很清楚fortunate幸运的是Itwasquiteplainthatshedidn twanttocome Howisitpossiblethatamancanfallsolow 注意 当形容词为下列形容词时 从句可用虚拟语气 为 should 动词原形advisable适当的 合理地better较好的preferable优越的 较好的essential必要的 important重要的insistent坚持的natural自然的necessary必要的desirable理想的urgent紧迫的unfair不公平的Itisunfairthatsomanypeopleshouldlosetheirjobs Itisessentialthatyou should winthevoters hearts Itisimportantthatthismissionnotfail 2 it be n that从句commonknowledge常识anhonour非常荣幸ashame可耻awonder是个奇迹nowonder不足为奇afact事实goodnews好消息apity遗憾aquestion问题Itisawonderthatheisstillailve Itisstillaquestionwhenweshallhaveoursportsmeet 注意 在此句型中 如果表示惊讶 遗憾等感情 that引导的从句谓语动词常用虚拟语气 should 动词原形 但如果表示的事实 谓语动词就不用虚拟Itisapitythatyoushouldhavetoleave 很遗憾你不得不离开Itisapitythatyouleft 遗憾的是你离开了 3 It be 过去分词 that从句Itissaidthat 据说 Itisreportedthat 据报道 Itisbelievedthat 据认为 Itisannouncedthat 据宣布 Itmustbepointedoutthat 必须指出 Ithasbeenprovedthat 已证明 Itisestimatedthat 据估计 Itmustbeadmittedthat 必须承认 Itcanthusbecoucludedthat 可以由此得出结论 Itwasreportedthattheyhadbroughtdowntwoenemyplanes 击落飞机 注意 如果过去分词表示 建议 命令 愿望 等含义的词 从句用虚拟语气 should 动词原形 suggested建议的ordered命令的requested要求的desired希望的demanded要求的required要求的recommended建议的decided决定的insisted坚决要求的commanded命令的 Itisrecommendedthattheproject should notstartuntilallthepreparationshavebeenmade Itwassuggestedthathe should jointheclubactivities 4 It 不及物动词 that从句 此句型中的that从句可以看做是句子的主语 但不能放句首 其句型为 Itseemsthat 好像是 Ithappenedthat 碰巧 Itfollowsthat 由此可见 Itmattersthat 要紧的是 Itoccurredtomethat 我突然想到 Itstruckmethat 我突然想到 Didn titoccurtoyouthatyourhusbandmightbelate Itissaidthattheyareahappypair it用作宾语 it作宾语 指代前面提到的一样东西 一个动物 一个婴儿或一件事情Didyouseethesnake Yes Isawit Howaboutthebaby I lltakecareofit Haveyougotmyexpressmail Yes I vegotit IfIhaveimprovedinanyway Ioweitalltoyou it作形式宾语 常用在下列动词后 consider think find count 把 认为 feel judge有下列几个常见句型 1 主语 及物动词 it 形容词 作宾补 不定式 真正宾语 常见形容词有 possible很可能difficult困难的impossible不可能wise明智的unwise不明智的necessary必要的interesting有趣better更好些wrong错误的Theyjudgeditbettertoputoffthemeeting Ifeltitnecessarytomakeeverythingclear 2 主语 及物动词 it 名词 作宾补 不定式 真正宾语 常见名词有one sduty某人的职责anhonour非常荣幸commonknowledge常识aquestion问题one sbusiness某人的事awonder是个奇迹nowonder不足为奇goodnews好消息ashame可耻apity遗憾 I llmakeitmybusinesstohelpher Idon tthinkitaquestionforhimtofinisheverythinginoneweek 3 主语 及物动词 it 名词 形容词 过去分词 作宾补 that从句 真正宾语 常见名词有 one sduty某人的职责anhonour非常荣幸commonknowledge常识aquestion问题one sbusiness某人的事awonder是个奇迹nowonder不足为奇goodnews好消息ashame可耻apity遗憾 常见形容词有 possible很可能difficult困难的impossible不可能wise明智的unwise不明智的necessary必要的interesting有趣better更好些wrong错误的 Theykeptitquietthathewasdead Weallthinkitawonderthattheyfinishedtheprojectinsuchashorttime Wehearditsaidthatthemeetingwouldbepostponed 4 主语 及物动词 it 名词 形容词 作宾补 动名词 真正宾语 在此句型中常见的形容词及名词有 nogood nouse awasteroftime fun hardwork apity awonder dangerous difficult senseless useless foolish nice tiring funny hard interesting worth worthwhile terribleHefounditnousewritingtohim Ithinkitdangerousswimminginsuchadeepriver 5 it作宾语 用在某些特殊句型中Seetoitthatyouarenotlateagain 注意别再迟到了Youcanputitthatitwasarrangedbefore 你可以说这是以前安排的Youmanydependuponitthatweshallneverloseheart 你放心我们绝不会灰心I dappreciateitifyouwouldliketoteachmehowtousethecomputer 句型为appreciate like love hate it if that wh 从句 it作主题的强调句 it作主题强调句为 itis was 被强调部分 that who 其余部分被强调部分可以是原来句子的主语 宾语 主语或宾语补足语 状语 强调的如果是原因状语从句 只能由because引导 不能由since as或why引导 不能被强调的部分是表语 谓语动词或though although等引导的让步状从 1 当被强调的是主语 主语是人时 可用who或that等引起后面部分 否则用that 被强调的是主语 要使用主格JohnmighthaveboughtanewbookforMaryyesterday ItisJohnwho thathaveboughtanewbookforMaryyesterday 强调主语 Itwasshewho thatsuggestedthathegotoNewYorkinordertogetadirectflight 2 当被强调的时宾语 宾语时人时 可用whom或that引起后面的部分 被强调的是物时 用that或which 不常见 JohnmighthaveboughtanewbookforMaryyesterday Itisanewbookthat whichJohnmighthaveboughtforMaryyesterday Itisthisnovelthat whichtheytalkedaboutlastweek Itiswherethemeetingwillbeheldthawewanttoknow 强调宾从 3 当被强调的是主语补足语或宾语补足语时 用that引起后面部分Itis IronMan thatheiscalled 强调主补 Itwaschairmanofthecommitteethatweelectedher 强调宾补 Itisredthathehaspaintedthedoor 强调宾补 4 当被强调的是状语时 用that引起后面部分 而不用when或where等ItisforMarythatJohnmighthaveboughtanewbookyesterday 强调状语 Itwasbecausethewaterhadrisenthattheycouldnotcrosstheriver 原因状从 ItwasyesterdaythatImethiminthestreet 时间状从 ItwasataneveningpartythatIfirstsawher 地点状从 5 not until 结构中的强调形式Itis wasnotuntil that Myfatherdidn tcomehomeuntil12lastnight Itwasnotuntil12lastnightthatmyfathercamehome Ididn tknowituntilhetoldme ItwasnotuntilhetoldthatIknewit 6 Itis that强调句的疑问句一般疑问句把is was提前Wasitshethatbrokethewindowyesterday 特殊疑问句要在一般疑问句前加上特殊疑问词Whyisitthatsilverisnotwidelyusedasconductor Whyissilvernotwidelyusedasconductor 非强调句型 WhenandwherewasitthatyougottoknowProfessorSmith Whatkindofworkisitthtyouwant 7 有时可用Itmightbe that Itmusthavebeen that 句型表强调Itmightbeateacherthatheisnow ItmusthavebeenbecauseIwasnewthattheydistrustedme ItmusthavebeenMarywhosebrotherhelpedmewithmyluggage 8 强调句型与其他句型区别强调句型去掉Itis was who that之后 句子结构仍旧完整 去掉之后不完整的可能是主从 定从或其他从句 被强调的部分译成汉语时 也要译成被强调部分 无法这样翻译的就不是强调句Itistheabilitytodothejobthatmattersnotwhereyoucomefromorwhatyouare 去掉后 Theabilitytodothejob notwhereyoucomefromorwhatyouare matters Thankyouforwatching 37