英语四级英语语法知识：限制性和非限制性定语从句，下边大伙儿梳理的专业知识，期待能够为大伙儿提供帮助，一起来学习一下吧。
限制性和非限制性定语从句
1) 定语从句有限制性和非限制性二种。限制性定语从句是先行词不能缺乏的一部分，除掉它主句含意通常不确立;非性定语从句是先行词的额外表明，除掉了也不会危害主句的含意，它与主句中间一般 用分号分离，比如： This is the house which we bought last month.它是大家上一月买的那幢房屋。(性) The house, which we bought last month, is very nice.这幢房屋很美，是大家上一月买的。(非性)

2) 当先行词是专业名词或物主代词和指示代词所装饰时，之后的定语从句一般是非限制性的，比如： Charles Smith, who was my former teacher, retired last year. 查里·阿诗丹顿上年退居二线了，他以前是亲爱的老师。 My house, which I bought last year, has got a lovely garden.我上年买的的那幢房屋带著个好看的花苑。 This novel, which I have read three times, is very touching. 这部小说集很迷人，我已经读过三遍。
3) 非限制性定语从句还能将全部主句做为先行词, 对其开展装饰, 这时候从句谓语动词要用第三人称奇数，比如： He seems not to have grasped what I meant, which greatly upsets me. 他好像没把握住您是什么意思，这使我烦心。 Liquid water changes to vapor, which is called evaporation. 液态水变成蒸气，这就称为挥发。 表明：关系代词that和关系副词why不可以正确引导非性定语从句。