（美国）PG-13级（13岁以下儿童必须在家长指导下观看的电影） In the United States, films that are labelled PG-13 are not considered suitable for children under the age of thirteen, but parents can decide whether or not to allow their children to see the films. PG is an abbreviation for 'parental guidance'. （美国）PG-13级（13岁以下儿童必须在家长指导下观看的电影）