一、关系代词 引导限制性定语从句的关系代词在作宾语、表语时可省略,但作主语和非限制性定语从句时不可省略。 eg:1、I have been to the city twice (that/which) you just visit. 2、After a score of years, Johnson is not the naughty boy (who/that) he used to be. 二、关系副词 1,在某些表示时间的名词后关系副词常省略,如the time, every time, the moment 等 2,在某些表示地点的名词后关系副词有时也可以省略,如the place 3,先行词 the reason 后面的关系副词可省略 4,当先行词是 way 时,关系副词常省略本回答被提问者采纳