主语从句¶

主语从句的引导词¶

That引导陈述句，无意义，但不可以省略(英语中为了明确主从句划分，习惯给从句加上引导词)。
- We eat meals every day. + This is important.
  
  We eat meals every day is important. X(主语是we还是we eat meals every day,双动词eat, is?)
  
  That we eat meals every day is important.
if/whether引导一般疑问句，意为是否。(if引导主语从句时不用于句首,可用于形式主语对应的真实主语从句中)
- Are you happy? + It is hard to say.
  
  Are you happy is hard to say. X
  
  Whether you are happy is hard to say.
- Can you swim? + It is hard to say.
  
  Whether you can swim is hard to say.
- Do you like beef? + It is hard to say.
  
  Whether you like beef is hard to say.
特殊疑问词引导特殊疑问句
- Where will they go? + It is a question.
  
  Where they will go is a question.

主语从句的语序：陈述语序(主语+动词).

Is he an elephant? ___ is a question.
- Whether he is an elephant is a quesiton.
Does he like elephants? ___ is a question.
- Whether he likes elephants is a question.(单三likes)
Who will the man meet? ___ is unknown.
- Who the man will meet is unknown.
What made him so happy? ___ is unknown.
- What made him so happy is unknown.(主语就是what)

Whether he likes pigs is unknown.(主语从句 + 系 + 表)
- It is unknown if/whether he likes pigs.(形式主语 + 系 + 表 + 真实主语从句)
Where they will go is a question.
- It is a question where they will go.