the reason why ，why 代替先行词 reason 在定语从句中状语，表原因；the reason which / that ， which / that 代替先行词在定语从句中主语、宾语或表语。如：The reason why he was late is that he couldn't catch the first bus. 他来迟的原因是他没赶上第一班车。（状语）The reason that / which he explained to his teacher is not reasonable. 他向老师解释的理由一点都不合理。 （宾语）The reason that / which is obvi...
