According to the newly-made traffic regulation, whoever drives through red light be fined at least 200 dollars. A.shall B.may C.would D.should 答案: A19.如图1,等边三角形ABC中,点D在AB上(点D与点A,B不重合),DE⊥BC,垂足为E,点P在BC上,且DP∥AC,△B′DE′与△BDE关于DP对称.设BE=x,△B′DE′与△ABC重叠部分的面积为S,S关于x的函数图象如图2所示(其中0<x<$\frac{1}{2}$,$\frac{1}{2}$≤x<m与m≤x<n时,函数的解析式不同).(1)填空:等边三角形ABC的边长为2,图2中a的值为$\frac{\sqrt{3}}{8}$;(2)求S关于x的函数关系式,并直接写出x的取值范围.