New Words & Expressions:alphabet 字母表            prime 素数，质数                displacement 位移    proportional 成百分比        domain 定义域      the real-valued function实值函数edge 棱，边         spring constant 弹性系数         graph 图，图形      limit 极限               stretch 拉伸         volume 体积，容积，卷            
2.6 函数概念与函数思想Function concept and function idea
New Words & Expressions(二)P59:measurable 可测       mapping 映射       
Various fields of human have to do with relationships that exist between one collection of objects and another.
6-A Informa ...