Another popular spectator sport, which is known as the sport of kings, is horse-racing, which is controlled by the Jockey Club.
译文：另一种以特大型运动著称的流行观赏运动是赛马，这种比赛由赛马总会控制。
本句话中，两个which引导的定语从句分别对前面的名词“spectator sport”和“horse-racing”，如果去掉这两个定语从句，句子就比较简单“Another popular spectator sport is horse-racing.”
请再看下例：
Each course which a student attends gives him a credit which he may count towards a degree.
译文：学生所上的每门课都将给他一个学分，当学生把所得学分累加到一定数量就可以获得一个学位。
本句子的表象也是有点复杂，但是如果我们明白定语从句可以限定名词，就可以把定语从句的部分先括起来跳过不看，抓住主干。第一个从句which a student attends到这里已经完整，所以括起来，同理第二个从句which he may count towards a degree，剩下的即为主干Each course gives him a credit.在翻译时，要注意汉语句子的结构平衡，所以一般把短的定语从句放在被限定名词前面翻译，而把相对较长的定语从句放在被限定的名词后面翻译。
有时候，定语从句的引导词如果在从句中作宾语，那么引导词可以省略，如下例：
Pollution and waste is a problem everyone can help to solve by cutting out unnecessary buying, excess consumption and careless disposal of the products we use in our daily lives.
本句话的主干就是开头部分Pollution and waste is a problem.在problem后面紧跟着everyone can help to solve这个定语从句，省略了引导词that，by后面引导的是限定动词solve的状语by cutting out unnecessary buying, excess consumption and careless disposal of the products。在状语部分，最后是名词products，后面又有一个省略that的定语从句(that) we use in our daily lives。显然，省略引导词后，定语从句判断的难度会加大，但是我们可以根据句子的含义来判断句子和前面名词的限定关系。