主语，宾语，定语从句构成形式由特殊疑问代词，副词以一般陈述语句形式构成。这是相同点，状语从句由特定引导词连接。
主语从句以完整句子形式位于复合句放于句首，多做主语。相当名词或代词，然后按一般语句结构系表或谓宾来组成完整语句。
What he does makes us unhappy.
宾语从句以完整语句位于复合句中，直接置于谓语动词后或位于宾语后作简接宾语或由if/whether引导词连接。由how/what/which/why/where/when/who/whom等词引导连接从句，当how从句作方式状语，what作宾语，which和名词连用从句作主语时，宾语从句可用省略简化形式。
I don't know what I can do/how to do it/what to do.
He told me he. had finished his homework.
She asked me if I could come on time.
表语从句以完整语句形式位于复合句中系动词be后面作表语。
It's why He comes late.
my dream is I can become a teacher one day.
定语从句根据主句中的先行词人，物，时间，地点以相应的关系词that/who/whom/which/When/where引导陈述语句构成从句位于先行词后作定语。
从句中who指人作主语，whom作宾语，从句中可省略。which指物可作主语或宾语，宾语时可省略，三者位于从句句首，用于非性定语从句，用来补充说明先行词意义，对语句含义无影响，可省略 ;when/where从句位于句首，不能省略，用于性定语从句。用来具体说明先行词的意义不可或缺不能省略。 举例：
非限定性：He doesn't like the boy (who is)quarrelling with others.
Let's go the place (which)we don't go to
限定性： You'd better finish your homework today When I will check it
Don't go to the park where one boy is dead.
状语从句具体分目的状语，时间状语，方式状语，条件状语，原因状语，结果状语，让步状语从句。以完整语句形式在复合句中作各个状语成分。
目的状语不需要引导词，按一般语句结构构成多位于主谓语句中和不定式to搭配表示目的。
We do It to we can learn more knowledge about it.
条件状语多由引导词if连接。用于祈使句中。
If you can't obey the rule, you will be punished.
原因状语多由because作连词引导从句，作状语，表示原因
The meeting will be put off to next Friday because it's rainy this week
让步状语从句由No matter 连接用于复合句中。
No matter what You do, I still hate you
