主语
主语的类别
可做主语的词类具有名词的特征，包括名词，代词，动名词，不定式短语，名词性从句，名词短语等
名词作主语
代词作主语
he, she, I, they, you, we等
动名词或不定式短语作主语
在英文中动词不能直接作主语，需要将它转换成不定式(表示未做过的事(如理想，梦想，目的，计划等))或动名词(表示已经做过的事或经验)
1 | Working with him is fun |
防止动名词或不定式短语作主语导致主语过长
用it代替它，将真正的主语放到句子最后；动名词移到句尾时，要改为不定式短语
1 | Listening to music is my hobby. |
1 | To buy a house for my patents is one of my plans |
名词性从句作主语
英语中句子不能直接作主语，需要写成名词性从句
名词性从句的种类
that从句
在陈述句前直接加上that。
1 | He doesn't study -> that he doesn't study |
whether从句
由一般疑问句变成，当一be动词开头时，be动词还原，再在句首加whether；当由一般助动词(may，will, mus, have, should, can)开头，助动词还原，前面冠以whether；当以do，does, did助动词开头时，去掉它，动词写为应有的时态和人称变化，再加whether
1 |
特殊疑问词引导的名词性从句
特殊疑问词(what, which, who, where, when, how, why)
问句有be动词时，be动词还原，保留疑问词
问句有一般助动词时，还原助动词，保留疑问词
问句有do, does, did等助动词时，删除，再还原动词时态和人称变化
1 | when will they do it? -> when they will do it |
1 | is there a man there? -> whether there is a man there |
1 | he never tells lies -> that he never tells lies |
1 | how did it happen? -> how it happened |
1 | has he finished the work? -> he has finished the work |
注意：当who, what, which为疑问代词，若在句中作主语，则变成名词性从句时，结构不变
1 | who did it? -> who did it? |
名词性从句作主语时应该注意的事项
导致主语过长，可以用it代替，真正的主语置于句末
1 | that he never lies is true |
1 | whether he can do it remains to be seen |
名词短语作主语
名词短语由：疑问词+不定式短语。由名词性从句简写而成
1 | where to live is not dicided yet. |
1 | whether to go depends on how much money we have |
表距离的地方副词短语亦可作主语
1 | from Shanghai to Beijing is about 1000 kilometers. |
细谈名词性从句的功能
名词性从句都可以作主语
名词性从句都可以作动词宾语
名词性从句作介词宾语仅’慧怡’可以
若that从句要作介词宾语，那么要对作适当改变, 有如下几种方法：
a. 介词 + the fact + that从句(that从句作the fact 的同位语)
1 | I'm worried about the fact that he doesn't study. |
b. 删除that，从句主语变所有格，动词变动名词
1 | I was surprised at that he sang so well 错 |
1 | I'm worried about that he doesn't study 错 |
be + 形容词 + that从句
1 | I was surprised at that he sang so well |
名词性从句都可以置于be动词之后
whether从句使用注意事项
whether可与or not连用，也可以将or not省略；作宾语时可以将whether换成if，作主语或介词宾语时不可以替换
1 | I don't know whether he'll come |
