偏头痛的临床特点不正确的是()
A.可表现为搏动性头痛
B.长期反复发作的头痛
C.头痛程度较轻
D.多为一侧头痛
E.精神紧张时可加重
参考答案:C
—What do you think of Fred and Mark, Mr West?
—Either of them can take this job, but I wonder who does things ______. [ ]
A. the most careful
B. more careful
C. more carefully
D. most carefully
运行的离子交换器树脂层分为三个区域,水流最后流经的区域为()。
A.失效层
B.工作层
C.保护层
D.未交换层