A.0.8~1.1 B.0.9~1.2 C.1.0~1.3 D.1.2~1.5
A.被動支護 B.主動支護 C.讓壓支護 D.鋼性支護
A.沖擊危險 B.厚度大的特點 C.?dāng)鄬佑绊?br /> D.頂板淋水