1、Unit 4 Astronomy the science of the stars主语从句语 境 自 主 领 悟先观察原句后自主感悟What it was to become was uncertain until between 4.5 and 3.8 billion years ago when the dust settled into a solid globe.The earth became so violent that it was not clear whether the shape would last or not.What is even more important
2、 is that as the earth cooled down，water began to appear on its surface.It was not immediately obvious that water was to be fundamental to the development of life.What many scientists believe is that the continued presence of water allowed the earth to dissolve harmful gases and acids into the oceans
3、 and seas.So whether life will continue on the earth for millions of years to come will depend on whether this problem can be solved.1.以上各句皆为主从复合句，句中黑体部分为名词性从句作主语，称之为主语从句。2.what引导主语从句，what在从句中作表语(句)，主语(句)，及宾语(句)。3.whether引导主语从句，意为：是否(句)。4.可用it作形式主语，真正的主语为名词性从句(句由that引导主语从句)。一、主语从句的基本用法1主语从句的引导词类别例词说
4、明从属连词that，whether两者在从句中均不作成分，只起连接作用；that无实义，whether表示“是否”。连接代词who，what，which，whoever，whatever等在从句中作主语、宾语、表语、定语等成分。连接副词when, where，how，why等在从句中作时间、地点、方式、原因状语等成分。That you are coming to London is the best news I have heard this long time.你将来伦敦是好久以来我听到的最好的消息。Whether it will do us harm remains to be seen
5、.它是否对我们有害还要看一看。What I have seen today has made a very deep impression on me.今天我的所见所闻给我留下了非常深刻的印象。Whoever breaks this law deserves a fine.触犯本法者应予以罚款。Whichever(of you)comes in first will receive a prize.(你们中)谁先进来谁得奖。When we will have a meeting is an important question.我们何时举行一次会议是个重要的问题。Where we shall
6、do the test is still under discussion.我们在什么地方做这个实验还在讨论。名师点津主语从句中连接词的选择技巧(1)根据连接词在从句中所作的语法成分。(2)根据连接词在从句中的意义。即时训练1用whether，that，whoever填空That she became an artist may have been due to her fathers influence.Whether we will hold a party in the open air tomorrow depends on the weather.Every year，whoever
7、 makes the most beautiful kite will win a prize in the Kite Festival.2it作形式主语为保持句子平衡，常把主语从句后置，而用形式主语it代替。it作形式主语时常用于以下句型：句型说明It系动词形容词主语从句常用于此句型的形容词有important，(un)likely，possible，necessary，natural，wrong等。It系动词名词主语从句常用于此句型的名词有fact，idea，honour，question，pity等。It系动词过去分词主语从句常用于此句型的过去分词，有known，proved，said，
8、decided，suggested，thought等。It不及物动词主语从句常用于此句型的动词有appear，happen，seem，occur，matter等。Its possible that he has been to Beijing.他有可能去过北京。Its a pity that you didnt attend the meeting.你没参加这次会议太可惜了。It seems that it is going to rain.看起来好像要下雨。It is important that he should know about this.他应该知道此事是重要的。It is sug
9、gested that the meeting be put off.有人建议会议延期召开。名师点津在“Itbe过去分词主语从句”结构中，过去分词若为suggested/ordered/required/advised等，主语从句中的谓语用“(should)do”。在“Itbe形容词主语从句”结构中，若形容词为important/necessary/strange等，主语从句中的谓语用“(should)do”。即时训练2完成句子很可惜你不能来参加我的生日聚会。Its a pity that you cant attend my birthday party.有人建议这位老人到乡村休息一下。It
10、s suggested that the old man should go to the countryside to have a rest.在我看来你好像不赞成这个计划。It seems to me that you disagree with the plan.二、主语从句中应注意的问题1从句要用陈述语序How he succeeded is still a puzzle.他是如何成功的仍然是个谜。2主谓一致(1)从句作主语时，主句的谓语一般用单数形式。Where he will get a job after graduation has puzzled him much.毕业后到哪
11、儿找一份工作使他很困惑。名师点津what引导主语从句时，有时主句谓语动词应与主句中作表语的名词保持一致。What the school needs most are books.这所学校最需要的是书。(2)如果由and连接两个或两个以上的主语从句作主语时，谓语动词用复数；由两个或多个连接词引导一个主语从句时，谓语动词用单数。When they will start and where they will go have not been decided yet.他们将在什么时候动身以及要去哪里还没定下来。When and where they will hold the meeting is
12、not clear.他们何时何地召开会议还不清楚。即时训练3单句改错When we will set off is still under discussion.will wewe willWhat he needs most are money.areisWhen and where the meeting will be held have not been decided.havehasThat the coal workers are still alive are a wonder.第二个areis.单句语法填空1It is often the case that anything
13、is possible for those who hang on to hope.2Your support is important to our work.Whatever you can do helps.3Where Li Bai，a great Chinese poet，was born is known to the public，but some wont accept it.4How we understand things has a lot to do with what we feel.5Exactly when the potato was introduced in
14、to Europe is uncertain，but it was probably around 1565.6When the delayed flight will take off depends much on the weather.7I think what impresses me about his painting is the colours he uses.8Some people believe what has happened before or is happening now will repeat itself in the future.9What make
15、s the book so extraordinary is the creative imagination of the writer.10What you said at the meeting describes a bright future for the company.完成句子 1有人命令操场建设下周完成。It is ordered that the construction of the sports ground should be completed next week2现在她正在买的东西是一些杂志。What she is buying now are some magazines.3很明显刚刚有人来拜访过他。It is clear that somebody came to visit him just now.4这个地区的争执(dispute)何时结束让很多人困惑。When the dispute in this area will stop puzzles many people.5她没有出席婚礼宴会的原因是她头痛。Why she didnt attend the wedding party is that she had a headache.
