You use she to refer to a woman, girl, or female animal who has already been mentioned or whose identity is clear.
双语例句
例：
When Ann arrived home that night, she found Brian in the house watching TV.
安那天晚上到家时，发现布赖恩正在屋里看电视。
例：
She was seventeen and she had no education or employment.
她17岁了，既没有受过教育也没有工作。
2.?她（代指不分性别的所有人）
Some writers may use she to refer to a person who is not identified as either male or female. They do this because they wish to avoid using the pronoun 'he' all the time. Some people dislike this use and prefer to use 'he or she' or 'they'.
双语例句
例：
The student may show signs of feeling the strain of responsibility and she may give up.
那个学生可能表现出了责任感到有压力的种种迹象，她很可能会放弃。
3.?她（代指国家或民族）
She is sometimes used to refer to a country or nation.
双语例句
例：
The country needs new leadership if she is to play a role in future development.
国家要在未来的发展中发挥作用，就需要新的领导班子。
4.?她（代指汽车、机器或船只）
Some people use she to refer to a car or machine. People who sail often use she to refer to a ship or boat.
双语例句
例：
The Seaflower was being repaired, but soon she was fit to sail again.