Doctors have said that as many as 50 percent of patients don’t take medicine ____ directed.

A．like

B．so

C．which

D．as

生物滤池的填料应采用高强、耐腐蚀、颗粒匀称、（）的材料，一般宜采用碎石、炉渣或塑料制品。

A.冷冻处

B.加热处理

C.消毒处理

D.比表面积大