师生比例
the ratio of teachers to pupils
比较比例方法
direct comparison proportional method
师生比
Teacher-student ratios
Pupil-teacher ratios
proportion between teachers and students
teacherpupil ratio
the rate between teachers and students in number
固定比例生产函数
fixed-proportional function
可变比例生产函数
variable proportional function
衍生比例定律
derivative proportional law