试用自己学习过的等高线知识绘制数学模型：半球体
（提示:1、要正确设计科学的图例和注记；2、要注意球面上不同区域的坡度。
略
Chinese handwriting is an important part of our culture, so young people are required to _____ handwriting.
A．take away
B．take up
C．take in
D．take out
什么是特定要素模型，试将其与要素禀赋论进行比较。
