衡量岩石(块)风化程度的指标
参考答案:(1)定性指标:颜色、矿物蚀变程度、破碎程度及开挖锤击技术特征等。(2)定量指标:风化空隙率指标Iw、波速比指标kv和风化系数kfδ等。
--- Listen! David is talking happily with his mother in the next room.
--- It ______ be his mother. She has gone to Yunnan to be a volunteer doctor.
A.should
B.must
C.can’t
D.mustn’t
影响商品价格的主要因素有()三种。
A.成本因素
B.供求关系
C.竞争因素
D.地理位置