请说出防风的来源、主产地、药用部位、主要成分、鉴别特征及功效。

最明显的鉴别特征，习称（）

A.菊花心 

B.过桥 

C.云绵花纹 

D.怀中抱月 

E.筋脉纹 

F.珍珠疙瘩

It is said that B. Shaw’ s play Mrs. Warren’ s Profession, has a p realistic theme, which fully reflects the dramatist’s Fabianist idea. What’s the theme of the work