谁能解释一下名词性从句和定语从句 谢谢

名词性从句是指从句作名词在句中充当的成分：主语、宾语、表语和同位语
What he said sounds right.主语从句
I don't know where he has gone.宾语从句
That is why he was late.表语从句
The news that China had won excited all Chinese.同位语从句
定语从句是指从句作定语修饰某一名词或代词。
I don't know the boy that is standing over.