彩色多普勒成像时不影响帧频的因素是
A．角度大小
B．深度
C．探头频率
D．滤波器
E．脉冲重复频率
参考答案：D
Could you ,please? It's too loud. [ ]
A. turn down the radio
B. turn on the radio
C. turn on the TV
D. turn it on
什么是绝对坐标和增量坐标？
