客人使用卡拉OK演唱时，声音先通过（）转换成微弱的电信号，再经过处理把电信号变成声信号。
A.音箱
B.视盘机
C.话筒
D.电视机
参考答案：C
泵压和排量频繁变化并不影响岩屑代表性。
Which of the following activities should the nurse discourage the client with a peptic ulcer
A．Chewing gum.
B．Smoking cigarettes.
C．Eating chocolate.
D．Taking acetaminophen (Tylenol).
