关系代词as与which的用法区分 as 和which的一样点 (1) as 和which都可引导非限制性定语从句，放在主句interesting book as we all want to read. 它是本我们大家都想读的好玩的书。 上面两句中的as就不能用which替换。 (2) as 在从句中常作宾语;作主语时，从句的谓语动词常为系动词，即：系表构造或被动构造。如： As you expected, he turned up on time. 正如你所愿，他按时到了。 As is said above, he has conquered the difficulty. 正如上面所说，他制服了困难。 (3) 当非限制性定语从句放到主句的前面时，引导词只能用as，而不用which。如： As is planned, we got there before eight. 正如打算，我们再把店前到达了那儿。
(4) As引导的非限制性定语从句指表示乐观的意义，与主句是顺理成章的关系，绝不能与之冲突。若非限制性定语从句表示一种消极的意义，则只用which。如： He has succeeded in his career, as / which we all hope. 他在事业中胜利了，这正是我们大家所盼望的。 Her grandma died last week, which made her very sad. 她的奶奶逝世了，这使得她很哀痛。 (5) 当非限制性定语从句的引导词前面有介词时，只能用which, 而不行用 as。如： He has a new computer, for which he paid nearly ten thousand yuan. 他有一台新电脑，这台电脑花了他将近一万元。 (6) 当关系代词代替主句中的宾语从句或复合构造(如：宾+补;不定式短语;动词-ing形式短语等) 时，一般只能用which, 而不用 as。如： She told us that there was something wrong with her bike, which was true。她告知我们说她的单车出了毛病，这话是真的。 He asked her to help him with his English, which she did. 他请她教他学英语，她确实帮了。 (7) 关系代词仅代表主句中的谓语局部时，从句中谓语局部被省略而只保存情态动词的否认式或助动词否认式，引导词一般只用which, 而不用as。如：
