更新时间：2018-12-10 03:19作者：王华老师
elementary: adj. 初步的，基本的
lay the foundation for: 为……奠定基础
footprint: n. 脚印
万能句型：
As the old Chinese saying goes, only through reading thousands of books can one write fluently.
The title of the picture further points out that…
The picture is meant to…
A brief review of … demonstrates …
The same principle applies to…