单项选择题
A.水平仪 B.经纬仪 C.铅直仪 D.钢卷尺
A.P•O42.5 B.P•O42.5R C.P•Ⅰ42.5 D.P•Ⅱ42.5
A.HPB300 B.HRB335 C.HRB400 D.HRB500