③和④两句是指如果定语从句中有作状语的介词短语，保留介词就要用关系代词，或用关系副词代替整个介词短语。eg:

　　I still remember that day.

　　I joined the Party on that day.

　　→I still remember the day on which I joined the Party.

　　本文结合定语从句中的及易混点，运用表格和详实的例句帮助大家进行了系统梳理，希望能够对各位考生理解定语从句有所帮助。

　　较后宁夏华图教师祝各位考生备考顺利，早日站在三尺讲台绽放光彩!