防碰撞装置有多种类型，()为其中之一。
A、机械式
B、液压式
C、超声波
参考答案：C
-- Not knowing what style of iPad to choose, _______.
A．some advice was given to Liming
B．Liming had to consult his IT teacher
C．so Liming had to consult his IT teacher
D．Liming’s IT teacher gave him some advice
C类仪表指除（）之外的所有仪表。
A.A类
B.B类
C.C类
D.参与装置质量控制
