G，代表general audience 无年龄限制：
Nothing that would offend parents for viewing by children.
PG，代表parental guidance suggested 家长指导级
Parents urged to give parental guidance. May contain some material parents might no like for their young children.
PG-13，代表parents strongly cautioned 特别辅导级
Parents are urged to be cautious. Some material may be inappropriate for pre-teenagers.
Contains some adult material. Parents are urged to learn more about the film before taking their young children with them.
NC-17，代表no one 17 and under admitted，17岁以下禁止观看
Patently adult, children are not admitted.