高中英语 unit 4 astronomy：the science of the stars period 4 grammar导学案新人教版必修3

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1、Unit4astronomy:thescienceofthestarsPeriod4Grammar学习目标：1.了解并掌握主语从句的相关概念；2.完成与主语从句相关的练习；学习重点：it作形式主语的各种句式及虚拟语气的使用。学习难点：主语从句引导词的正确选择。预习案课文原句分析(P25-26)1.wasuncertainuntilbetween4.5and3.8billionyearsagowhenthedustsettledintoasolidglobe.2.Theearthbecamesoviolentthatitwasn

2、otclear-3.isthatastheearthcooleddown,waterbegantoappearonitssurface.4.Itwasnotimmediatelyobvious5.isthatthecontinuedpresenceofwaterallowedtheearthtodissolveharmfulgasesandacidsintotheoceansandseas.6.stillremainsamystery.7.Sowilldependonwhetherthisproblemcanbesolved.

3、探究案主语从句：在复合句中充当主语的句子，通常放在主句的谓语动词之前,或由形式主语it代替，而从句后置放在句子末尾。句子结构：引导词+句子+主句谓语+主句其他成分一、主语从句的引导词从属连词that(无意义、无成分、不可省),whether（有意义、无成分、不可省）连接代词who(ever),whom(ever),what(ever),which(ever),whose(ver)（有意义、有成分、不可省）连接副词when(ever),where(ver),why,how(ever)（有意义、有成分、不可省）ThatTomdid

4、n’tpasstheexammadehismotherveryworried.Whetherwewillhaveameetingtomorrowhasn’tbeendecided.Whatisthemostimportantforusstudentsisstudyinghard.Thereare5bookshere.WhicheveryouwillchooseisOk.Whenandwherewewillgocampinghasn’tbeendecided.Itisnotclearwhyhewasabsentfromschoo

5、l.Howwecangetenoughmoneyisstillaproblem.二、如何确定主语从句的引导词原则：“缺什么补什么”（成分、意义）1.如果从句中缺主语、宾语、表语，指人时用who(ever)，whom(ever)或which(ever)(有选择范围），指物用what(ever)或which(ever)(有范围）；2.如果从句中缺状语用when(ever)，where(ver)，why，how(ever)；3.如缺定语，用what，which或者whose（修饰名词或代词）；4.什么都不缺，用that（无意义）或w

6、hether（有意义“是否”）。三、形式主语it有时为了使句子结构平衡,避免“头重脚轻”,常用it作形式主语,把主语从句放在主句的后面。例如:Itisapitythatshehasmadesuchamistake.这样就构成了下面一些常用句型:1.Itis+n.+从句　Itisapity/shamethat...遗憾的是……Itisasurprisethat…令人惊奇的是……Itisafactthat………是事实Itisanhonorthat………是非常荣幸的Itiscommonknowledgethat………是常识2.Iti

7、s+adj.+从句　It’scertainthat………是肯定的　Itislikely/possible/probablethat...很可能……Itisunlikely/impossible/improbablethat...不可能……Itisclear/obviousthat…很明显……Itisnecessary/important/natural/...that…+(should)do3.It+不及物动词+从句Ithappenedthat...碰巧……Itoccurredtomethat…我突然想起……Itseems/a

8、ppearsthat…似乎……4.It+be+过去分词+从句Itissaidthat...Itisreportedthat...Itisbelievedthat...“据.......”Itisknowntousallthat...四、主语从句中的虚拟1.在“Itisrequ