文档介绍：名词性从句主语从句宾语从句名词性从句表语从句同位语从句以that引导以whether/if引导名词性从句结构以特殊疑问句引导以what或wh-ever等连接代词引导(名词性关系从句)主语从句以that引导的主语从句That从句作主语时,常用it作形式主语①it+be+形容词(obvious,true,natural,surprising,good,wonderful,funny,possible,likely,certain,probable…)+that从句②it+be+名词词组(nowonder,anhonor,agoodthing,apity,nosurprise…)+that从句③it+be+过去分词(said,reported,thought,expected,decided…)+that从句即it+be+形容词/名词词组/过去分词+that从句形式主语真正主语在口语和非正式文体中,that可省略,尤其很短的句子,that不必要,但是that从句位于句首时,that绝不可省略whether引导的主语从句强调主语从句谓语句首只能用whether,不可用if代替主语从句在句末,whether和if均可特殊疑问词引导的主语从句常用it作形式主语连接代词who,which和连接副词when,where,how,why都可引导主语从句,不可省如句子是疑问句式,则必须用it引导名词性关系从句(以what或wh-ever等连接代词引导的名词性关系从句)what或wh-ever引导主语从句【例】:see,say,know,imagine,discover,believe,tell,show,think,consider,besure,beafraid等,在可以接复合宾语的动词之后如think,make,consider等,可以用it作形式宾语That从句一般不能充当介宾,偶尔可做except,in的宾语【例】heisagoodstudentexceptthatheisalittlebitcarelesswhether/if引导的宾语从句whether从句中不能有否定式介词后只能用whether,不能用if特殊疑问词引导的宾语从句能接特殊疑问词引导的宾语从句的动词很多,例如see,tell,ask,answer,know,decide,findout,imagine,suggest,doubt,wonder,show,discuss,understand,inform,advise等名词性关系从句(作动宾,介宾)表语从句that引导表语从句that不可省略Myidesisthatwe’,在句中不充当成分,没有意义,,不能用if注:从属连词if一般不用来引导表语从句,