A.地基面B.水平面C.相對(duì)D.絕對(duì)
A.急停按鈕B.電鈴C.向上運(yùn)行按鈕D.啟動(dòng)按鈕
A.85dB(A)B.86dB(A)C.87dB(A)D.98dB(A)