只能给你写这么多了!我也累的
先行词（n/pron） +关代/副 +定从
主语宾语 定语表语
人who/thatwho/whom/that/-whose that
物which/thatwhich/that/- whose that
〔注：关系代词作用：①代替作用②连接作用③在定语从句中充当成分（主语,定语,宾语,定语）〕
下列情况只用that而不用which
something（指物的不定代词） the first+n（序数词）the very+n（正是） the best+n（最高级） just+the+n the only+nall/few/little all/few/litter/any/some+n 人+物
2.October 1.1949 is a special day（that/which/—）China was found on.
October 1.1949 is a special day（on which=when）Chaina was founded.