第一章 句子的构成
任何一个句子一定是由主语及动词构成 S+V
有时主语可以省略，而构成了祈使句。这种祈使句由原形动词（也称为动词不定式）引出。
祈使句变成否定形式时，要在原形动词前加Don't
第一节 可充当主语的词类
名词、代词、动词转变过来的动名词或不定式短语、名词从句、名词短语、表距离的地点副词短语等可以做主语。
动词绝不可直接充当主语，一定要变成动名词或不定式短语。
动名词做主语，通常用以表示已知的事实或经验。
不定式做主语，通常表示一种意愿、目的或未完成的事。
注意：不定式或动名词短语做主语时，往往会形成主语过大的现象，故通常均用代码it做主语，置于句首，而将真主语（亦即不定式或动名词短语）移至句尾。动名词移至句尾时，通常改为不定式短语。
注意：被it代替的动名词短语移至句尾，仍保留动名词形态而不变成不定式短语的用法并不普遍，初学语法者宜尽量避免。
以下句型属例外情形，it要代替动名词短语，不可使用不定式短语：
It is no use + 动名词短语
注意：It is no use + 动名词短语
= It is useless + 不定式短语
= It is of no use + 不定式短语
= There is no ( use | sense | point ) + in + 动名词短语
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句子不能当主语，一定要变成名词从句方可做主语。
所谓句子，就是一开头就是主语的结构。
名词从句一共有三种：that从句、whether从句、疑问词所引导的从句。
任何一个主语起首的句子前面冠以that即成that从句。
whether从句是由可用yes/no回答的问句变化而成
问句有be动词时：主语与be动词还原，前面冠以whether. Is he happy? -> whether he is happy
问句有一般助动词(can,will,may,should,ought to,must,have)时，主语与助动词还原，前面冠以whether. Can he do it?->whether he can do it?
问句有do,does,did等助动词时：主语与助动词还原，再将do,does,did去掉，后面的动词依人称和时态变化.
Did he come? -> whether he did come. -> whether he came.
Does he like it? -> whether he does like it. -> whether he likes it.
疑问词从句是由疑问词(when, what, how, where, why)等引导的问句变化而成。
问句有be动词时：主语与be动词还原，前面保留疑问词。What is he doing? -> what he is doing
问句有一般助动词时：主语与助动词还原，前面保留疑问词。Where can he find it? -> where he can find it
问句有do,does,did等助动词时：主语与助动词还原，前面保留疑问词，再将do,does,did去掉，动词依人称和时态变化。
What did he write?-> what he did write -> what he wrote.
When did he come? -> when he did com -> when he came.
注意：who,what,which(哪一个)为疑问代词，若在问句中做主语，变成名词从句时，结构不变。
Who came here? -> who came here
What happened lst night? -> what happened last night
Which was bought? -> which was bought 哪个被买走。。。
名词从句的功能：做主语；做动词的宾语；做介词的宾语；
注意：用whether或疑问词引导的名词从句可做介词的宾语，但that从句不可做介词的宾语。
遇到介语，且非要使用that从句时，其补救方法如下：
1）介词 + that fact + that从句 , 这样，就可用the fact 做介词的宾语，而that从句就成了the fact 的同位语。
2）保留介词，但不加the fact，且介词之后的that从句要做适当变化
第一步：除去that； 第二步：that之后的主语变成所有格；第三步：动词变成动名词；
I am worried about that he plays around all day. -> I am worried about his playing around all day.
注意：that从句若有助动词do,does,did时，去掉即可。
I am worried about that he doesn't study. -> I am worried about his not studying.
注意：that从句若有助动词will或would时，去掉即可，但也可以改为be going to,再将be 动词转变为动名词being.
I am sure of that the team will win the game.
->I am sure of the team's winning the game.
或I am sure of that the team is going to win the game. -> I am sure of the team's being going to win the game.
注意：从句若有以下助动词时，做下列变化：
may -> be likely to
can -> be able to
should/must -> be supposed to
再将be动词变成动名词being.
I am happy about that he may come -> I am happy about that he is likely to come -> I am happy about his being likely to come.
3）be + adj. + that从句
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去掉介词，将that从句放在形容词后面，使that从句成为副词从句（注：相当于传统语法中的状语从句），修饰该形容词。
I am worried about that he plays around all day. -> I am worried that he plays around all day.
I am sure of that the team has won the game. -> I am sure that the team has won the game.
有时介词之后也可以直接接that从句，前面不需the fact，形成惯用语，要牢记：
in that = because 因为
He is great in that he can speak five different languages.
except that 只可惜
He is nice except that sometimes he lies.
for all that 尽管 = with all that = not withstanding that
For all that he is nice, I don't like him.
= Despite the fact that he is nice, I don't like him.
= In spite of the fact that he is nice, I don't like him.
名词短语是由“疑问词+不定式短语”构成。
疑问副词 where to live ; whether to try again; when to talk to him; how to do it
疑问代词 what to do; whom to see; which to buy; whom to talk to
注意：疑问副词构成的名词短语中，疑问副词因为是副词的性质，故不做不定式短语中及物动词的宾语。但疑问代词构成的名词短语中，疑问代词因具有名词的性质，故一定要做不定式短语中动词或介词的宾语。因此what,whom,which在上述名词短语中，分别做do,see,buy,to(介词)的宾语。
表距离的地点副词短语做主语
From + 地点名词 + to + 地点名词，此为表距离的地点副词短语，亦可做主语，与单数的be动词并用
From Taipei to Taichung is about 160 kilometers.
It is about 160 kilometers from Taipei to Taichung.