定语从句（Attributive Clauses）在句中做定语，修饰一个名词或代词，被修饰的名词,词组或代词即先行词。定语从句通常出现在先行词之后，由关系词（关系代词或关系副词）引出。e.g. She is the girl who talked to me yesterday. 名词性从句（Noun Clauses）-主语从句、宾语从句、表语从句和同位语从句在句中做主语、宾语、表语和同位语的成份。e.g. I dont know who she is. (宾语) This is why I came here.（表语）区别：第一，定语从句有先行词，且先行词可以放入后面的从句中使从句完整；名词性从句中的主语从句、表语从句和宾语从句没有先行词，同位语从句有先行词但在从句中不做成分。e.g. The news that they told me excited me. （the news可以放入从句中，使句子完整，即they told me the news） The news that our team won exci
