Question

怎么区分形容词性从句和名词性从句？ 名次性从句中连接词选用，要借助句意吗?

Answer 1

形容词性从句一般就是指定语从句。
名词性从句通常指以下集中：主语从句，表语从句，宾语从句，同位语从句，插入语从句。

主宾表这三种从句非常好分辨，看他们所在位置和谓语的相对位置就知道了。

比较麻烦一点的是同位语从句，在很多语法书里，同位语从句都是出现在定语从句那一章（这么安排不无道理，但是我还是觉得非常不靠谱）。分别同位语从句还是定语从句——他们都是和名词有关系，定语从句做名词的形容词，同位语从句则为补充说明——关键看从句本身是否完整。定语从句会缺语法成分，而名词性从句是不缺语法成分的，也就是说，名词性从句的关系词that和关系连词，在此后的从句中完全不充当成分。

我不晓得你是不是大学生，如果你不是考研究生和博士生英语，又或者是外语专业，这些东西你都不需要太了解。如果是中学生和本科生，则完全不必理会。

Answer 2

名词性从句包括主语从句、表语从句、宾语从句和同位语从句。引导名词性从句的关联词有从属连接词、疑问代词、疑问副词、缩合连接代词、缩合连接副词等。究竟选用哪种关联词，要看句子的意思，比如从句中无疑问意义的，就用从属连接词that，有一般疑问意义的，用从属连接词whether，有特殊疑问意义的，则用疑问代词和疑问副词，当句子中缺少成分，而又不具有疑问意义的，我们可以用缩合连接代词和缩合连接副词来引导名词性从句。如：
That we shall be late is certain. （我们可以把形式主语it放在主语的位置，把主语从句放在句末，以避免句子头重脚轻，特别是当句子是被动结构、一般疑问句或感叹句时，更常用引词it作形式主语）
His first question was whether Holmes had arrived yet.
She asked me which computer I liked best.
I wonder what the problem is.
I can't understand why he was so late.
I don't have the least interest in what he is doing.
He is a slow starter but what he learns he learns well. （需要强调时，把宾语从句置于句首）
You can call me whatever you like. （缩合连接代词引导的从句是宾语的补语从句）
The fact that the money has gone doesn't mean it was stolen.
当主句的动词为过去时态时，名词性从句的时态也要向过去方向推一级，称为时态的呼应，如现在时态变为过去时态，过去时态变为过去完成时态，将来时态变为过去将来时态，情态动词如为现在时，也应作相应的改变，而情态动词的过去式则不变，或者变为相应的表示情态意义的短语的过去完成时，如：
He said he was sorry.
He said that the man had come at six.
She said he would come late.
He said that the man might come.
He said that he could （或had been able to）speak English when he was six.
She said that she must be frank with him.
He said that he ought to say nothing.
He said that they needn't stop me.
She said that if he had been there, he would have voted for the motion.
形容词性从句是作定语的，一般皆放在它所修饰的名词之后，这种名词称为先行词，引导定语从句的关联词为关系代词和关系副词，它们在从句中作主语、宾语、定语和状语等成分。关系代词有who，whom，whose，that和which。who是主格，指人，whom是who的宾格，也指人，that既可作主语，也可作宾语，既可指人，也可指物，which一般皆指物，可作主语，也可以作宾语，whose是who和which的所有格，在从句中作定语，多指人，有时也可以指物。关系副词有when、where、why等，在定语从句中作时间、地点和原因状语，when的先行词表时间，在从句中作时间状语，where的先行词指地点，作地点状语，而why的先行词只有reason，在从句中可以作原因状语。as、than、but也可以作关系代词，关系代词在定语从句中也可以作介系词的宾语，但是关系代词主格who与that作介系词宾语的时候，介系词放在从句的末尾，其余关系代词作介系词宾语时介系词则可以放在从句开首。定语从句可以分为限制性定语从句和非限制性定语从句，限制性定语从句前面不用逗号，非限制性定语从句前面一般有逗号，实质上它的功用相当于一个分句，或者相当于状语从句。that和why不引导非限制性定语从句。如：
A doctor is a person who looks after people's health.
The gentleman whom she encountered addressed her with courtesy.
Is he the man that sells eggs?
She wasn't on the train which arrived just now.
I'd like a room whose window looks over the sea.
July and August are the months when the weather is hot.
There are cases where the word is used as an adverb.
That is the reason why I like the movie "The sound of Music" best.
He was from Texas, as I knew from his accent.
You spent more money than was intended to be spent.
There is no rule but has some exceptions.
This is the book for which you asked.
The people who you were talking to are Swedes.
Here is the car that I told you about.
The textile mill has over eight thousand workers, 80% of whom are women.
Water, which is a clear liquid, has a lot of uses.
She is the only woman I know who can speak Spanish.
She read a poem which we thought was written by Shakespeare.
We don't like the room, which is cold.
All that glitters is not gold.
希望我能帮助你解疑释惑。