如图是我国土地资源分布图，按草地、林地、水田、旱地的顺序排列正确的是（　　）

给下列句子排出正确的顺序。

A. I see. My father is a postman, too.

B. Is your brother a postman? 

C. Really? Where does your father work? 

D. Yes, he is. He works in the post office near our school.

E. He works in the same post office with your brother.

____  ____  ____  ____  ____  

设△ABC的三边长分别为a、b、c，△ABC的面积为S，内切圆半径为r ，则r＝$\frac{2S}{a+b+c}$；类比这个结论可知：四面体S－ABC的四个面的面积分别为S₁、S₂、S₃、S₄，内切球的半径为R，四面体P－ABC的体积为V，则R＝(　)

松香在熔化过程中（　　）