1. 有时为了保持句子结构平衡或者为了加强语势，两个同位成分可能被分隔，如：
　　　　Only one problem still remains—the selling of these machines.

　　 2. 两个同位语之间插入一些引导词表示等同、举例，或突出某点。这些常见的引导词是：namely, that is to say, in other 　　　　words, or, for short, for example, such as, including, especially, particularly, mostly 等，如：
　　　　Susan is a good student; that is to say, she gets good grades in school.
　　　　Besides English he knows other foreign languages, such as French and Russian.
　　　　I want very much to read these new novels, especially the one you introduced.

　　 3. 两个同位语被一些修饰词分隔，如：
　　　　Dr. Smith, former director of our hospital, wrote many books on medicine.
　　　　Prof. Smith, at that time a college student, was fond of classical music very much.