英语当中的三大从句是状语从句，定语从句和名词性从句。

状语从句的引导词有: where,where, how,though，Although. if等。引导定语从句的引导词有关系代词有that,which，whom，whose，as.关系副词有when,where，why.引导名词性从句的有连接词that ,whether , if.连接代词有Which what, who,Whichever, whatever, whoever.连接副词有when，where，why, how.