宝贝，爱的是你，所以还是你！
根据从句与主句关系的紧密程度，定语从句又分为限制性定语从句和非限制性定语从句。从形式上看，限定性定语从句主句和从句之间不用逗号隔开，口语中使用时也不停顿；而非限定性定语从句与主句之间通常有逗号隔开，口语中使用时有停顿；从功能上看，限定性定语从句用于对先行词的意义进行修饰、限制和识别，如果去掉，就会造成句意不完整或概念不清；而非限定性定语从句用于对先行词起补充说明作用，如果省略，句意仍然清楚、完整。如：
People who take physical exercise live longer. 进行体育锻炼的人活得长些。(若把从句去掉句子就失去意义)
I went to the room which he had called the nuptial chamber.
我走进了他称之为洞房的房间。(若把从句去掉句子就失去意义或不完整)
His daughter, who is in Boston now, is coming home next week. 他女儿现在在波士顿，下星期回来。(若把从句去句子意义仍然完整)
另外，限制性定语从句与非限制性定语从句所修饰的先行词通常也有所不同：限定性定语从句的先行词只能是名词或代词，而非限定性定语从句的先行词则可以是名词或代词，也可以是短语或句子；另外，当先行词为专有名词或其他具有独一无二性的普通名词时，通常要用非限制性定语从句，而不用限制性定语从句。如：
Peter drove too fast, which was dangerous. 彼得开车很快，这是很危险的。(which指drive too fast)
He changed his mind, which made me very angry. 他改变了主意，这使我很生气。(which指整个主句)
They ran out of drink. Which actually didn't bother me because I wasn't drinking. (which指整个主句)
他们把酒喝完了。但实际上这对我来说无所谓，因为我不喝酒。
Mr. Smith, who is our boss, will leave for Japan next week. 我们的老板史密斯先生下周要去日本。(先行词为专有名词，要用非限制性定语从句修饰)
Her father, who has a lot of money, wishes her to study abroad. 她父亲很有钱，希望她出国学习。(先行词为表独一无二意义的普通名词，要用非限制性定语从句修饰)
