名词性从句复习it作形式主语.ppt

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1、Module3Unit2GrammarandusageLearninggoalslearnthatthepreparatorysubject/emptysubjectitisoftenusedtobalancethesentencewithalongsubject.Theemptysubjectitactsasitsgrammaticalsubjectandtherealsubjectisattheendofthesentence.ThatweshouldimproveouroralEnglishisimportant.Itisim

2、portantthatweshouldimproveouroralEnglish.preferablecorrectWhichoneisbetter?Preparatorysubject"it"Readthenotesonpage30.Preparatorysubjectit形式主语it通常情况下，当句子的主语很长（是从句,动词不定式或动名词短语时），我们一般用it作形式主语，让句子结构更加平衡，避免头重脚轻。形式主语it在语法上起到主语的作用，而句子的真正的主语则在句尾。whenweuseanounclauseasthesubje

3、ctofasentence.当句子的主语是从句时，我们一般用it作形式主语。a.(correct)Thatlanguagesborrowwordsastheyaredevelopingisinevitable.=(preferable)Itisinevitablethatlanguagesborrowwordsastheyaredeveloping.b.(correct)Whether“borrowedwords”aregoodorbadremainsaquestion.=(preferable)Itremainsaquestion

4、whether“borrowedwords”aregoodorbad.1.Wecanuseitasanpreparatorysubject.Preparatorysubject“it”:1.ThatwewouldbenotabletounderstandOldEnglishtodayiscertain.=ItiscertainthatwewouldnotbeabletounderstandOldEnglishtoday.2.WhetherEnglishwillcontinuechanginginthefutureiseasytoan

5、swer.=ItiseasytoanswerwhetherEnglishwillcontinuechanginginthefuture.3.Whenwecansetoffdependsontheweather.=Itdependsontheweatherwhencanwesetoff.(correct)Tomasteraforeignlanguageishard.(preferable)Itishardtomasteraforeignlanguage.b.(correct)TogainaccesstotheInternetisimp

6、ortantforus.(preferable)ItisimportantforustogainaccesstotheInternet.B.whenthesubjectisato-infinitive.当句子的主语是不定式时，我们一般用it作形式主语。C.whenthesubjectisav-ingform.当句子的主语是动名词v-ing时，我们一般用it作形式主语。a.(correct)Itisdifficulttostopsmoking.=(preferable)Smokingisdifficulttostop.b.(corre

7、ct)IttakesalotofmytimetravellingtoBeijing.=(preferable)TravellingtoBeijingtakesupalotofmytime.Weusuallyusethepreparatorysubjectitwithaclauseorto-infinitive(preferable),butwiththev-ingformweprefertherealsubjectatthebeginning.通常情况下，当句子的主语是从句或动词不定式时，我们一般用it作形式主语。当句子主语是动词的

8、-ing形式时，我们则一般将真正的主语置于句首，而不使用it作形式主语。Tip2.当seem,appear,happen,turnout和prove在句子中作谓语动词时，我们也可以使用形式主语it。Itseemsthathespeak