不定式作主语
不定式作主语 To+动词原形Nottodo解释:含有动词的性质,作宾语,状语/含有名词的性质,作主语/含有形容词性质,作定语/含有副词的性质,作状语。除谓语不可作之外,其它全部可。通常式:todo进行时:tobedoing完成时:tohavedone完成进行时:tohavebeendoingtodo:表示动作发生在谓语以后,Iwanttogohome.和谓语动词几乎同时发生tobedoing:表示和谓语动词同时发生tohavedone:发生在谓语动词之前Someonewasconsideredtohavedonesomething.tohavebeendoing:动作从过去开始一直连续到谓语动词这个动作的发生1 动词时,谓语动词经常用单数。比如:Todomorningexercisesisusefulforourhealth.做早操有利于我们的健康。Tosweepthefloorismydutyeveryday.天天打扫地板是我的责任。2 假如动词不定式太长,经常用it作形式主语,而将真正的主语动词不定式后置。比如:Ittookmehalfanhourtowalkthere我走到那儿花了半小时的时间。It'simportantforustolearnEnglishwell对我们来说,学好英语是主要的。下面归类五种句型:It+be+名词+todoIt'sourdutytotakegoodcareoftheold.Ittakessb+sometime+todoHowlongdidittakeyoutofinishthework?It+be+形容词+forsb+todoItisdifficultforustofinishwritingthecompositioninaquarterofanhour.It+be+形容词+ofsb+todoItisstupidofyoutowritedowneverything(that)theteachersays.Itseems(appears)+形容词+todoItseemedimpossibletosavemoney.注意:在句型中,常见表示客观情况的形容词,如:difficult,easy,hard,important,impossible,necessary等;在句型中,常见careless,clever,good,foolish,honest,kind,lazy,nice,right,silly,stupid,wise等表示赞扬或批评的词。在不定式前的sb,可看作其逻辑主语。这一句式有时相当于Sbis+形容词+todo句式。如:It'skindofyoutohelpmewithmyEnglish.=YouarekindtohelpmewithmyEnglish.