1. 与中文一样，分号用于分隔地位平等的独立子句。在某些情况下，使用分号比使用句点更显出子句之间的紧密联系，另外分号也经常与连接副词 thus，however，therefore一起使用(放在这些词语之前)。如 i realize i need exercise; however, i'll lie down first to think about it.
2. 在句子中如果已经使用过逗点，为了避免歧义的产生，就用分号来分隔相似的内容。如：the employees were tom hanks, the manager; jim white, the engineer; and dr. jack lee.
需要注意的是：一个完整的句子以大写字母开始，以句点结束。写英文时用逗点代替句点、分号、冒号或破折号叫“逗号错”，这正是中国学生所要避免的。请比较下列例句：
误：it was raining hard, they could not work in the fields.
(注意：上面句子中划横线的部分是两个不同的主语，而且逗点前后的句子是完整的——单独拿出来都能代表一个完整的意思。因此，用逗号违反了英文规定，即一个句子只能有一套主干。)
正：it was raining hard; they could not work in the fields.
it was raining hard. they could not work in the fields.
it was raining so hard that they could not work in the fields.
they could not work in the fields because it was raining hard.
it was raining hard, so they could not work in the fiel