單項(xiàng)選擇題
A.50 B.70 C.35 D.100
A.30mg/m3(20ppm) B.45mg/m3(30ppm) C.75mg/m3(50ppm) D.150mg/m3(100ppm)
A.閾限值 B.安全臨界濃度 C.危險(xiǎn)臨界濃度 D.4.3ppm以下
A.50% B.60% C.80% D.100%
A.防噴單根、防噴立柱 B.應(yīng)急旋塞、防噴立柱 C.應(yīng)急旋塞、防噴單根 D.防噴單根、應(yīng)急旋塞
A.常關(guān)、常開 B.常關(guān)、常關(guān) C.常開、常開 D.常開、常關(guān)
判斷題