定语从句有明显的先行词(名词或代词),还有引导从句的关系代词或副词(which,that/where,why,when）
1.关系代词（which,that）
它们所代替的先行词是事物的名词或代词,在从句中可作主语、宾语等,例如：(1) A prosperity which / that had never been seen before appears in the countryside.农村出现了前所未有的繁荣.（which / that在句中作主语） (2) The package (which / that) you are carrying is about to come unwrapped.你拿的包快散了.(which / that在句中作宾语,作宾语时关系词可省略）
2.关系副词（在句中作状语：why/where/when）
关系副词=介词+关系代词 why=for which where=in/ at/ on/ ...which (介词同先行词搭配) when=during/ on/ in/ ...which (介词同先行词搭配) ●where是关系副词,用来表示地点的定语从句,why是用来表示原因的定语从句,when用来表示时间的定语从句.如：(1) Shanghai is the city where I was born.(2) I still remember the day when I first came to the school.(3) Please tell me the reason why you missed the plane.
而非谓语,顾名思义,就是不能做谓语的词或结构,包括动词不定式,动词ing结构(动名词、现在分词),过去分词等.如：（1）I'm glad to meet you.（2）Seeing is believing.眼见为实./The problem being discussed is very important.正在被讨论的问题很重要.（3）Our class went on an organized trip last Monday.上周一我们班开展了一次有组织的旅行.
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