饮用水消毒常用（）
A.臭氧
B.漂白粉
C.过氧乙酸
D.石炭酸
E.氯
参考答案：E
解析：（0.2～0.5）mg/L氯常用于饮水消毒。
The police said they would not give up looking into other possibilities ____they find out what happened.
A．as
B．while
C．until
D．although
颗粒剂制备的关键工艺技术是（）
A.中药的提取
B.制软材
C.制颗粒
D.干燥
E.整粒
