A.關(guān)閉 B.開(kāi)著 C.視情況關(guān)閉或打開(kāi) D.不能開(kāi)著
A.1.8~2.3g/cm3 B.1.33~1.8g/cm3 C.1.39~1.70g/cm3 D.1.17~1.20g/cm3
A.0.05MPa B.0.3MPa C.0.2MPa D.0.1MPa