单项选择题
A.6~9度 B.7~9度 C.6~10度 D.7~10度
A.1,0.5m,0.5~1.Om B.1,0.5m,0.8~1.5m C.2,0.5m,0.5~1.Om D.2,1m,0.8~1.5m
A.软石、次坚石、坚石、特坚石 B.特坚石、坚石、软石、次坚石 C.坚石、次坚石、特坚石、软石 D.特坚石、坚石、次坚石、软石