單項(xiàng)選擇題
A.50B.60C.70D.80
A.1ppmB.2ppmC.3ppm
A.8B.10C.12
A.0.65~0.71B.0.65~0.72C.0.68~0.72D.0.68~0.71
A.100~125B.100~130C.115~125D.115~130
A.48~56B.50~56C.53~60D.54~58
A.6~15B.6~8C.8~15D.8~10
A.170~185B.170~190C.175~185D.175~190
A.0.4B.0.5C.0.6D.0.7
A.100B.80C.60D.50
A.5~75B.5~80C.10~75D.10~80