礼仪是一个人性格、（）、文化程度、道德修养的外化。
A、仪容仪表
B、服饰打扮
C、气质
参考答案：C
用离子交换树脂法提取总生物碱，所选择的树脂类型应是( )
A．大孔树脂B．弱酸型树脂C．弱碱型树脂D．强酸型树脂E．强碱型树脂
It's impossible for a child to do so much work within a short period of time, ______
A. isn't it B. is itC. has it D. hasn't it
