隧道超欠挖原因有()。
A.测量放样错误或误差较大
B.钻孔操作台架就位不准确
C.爆破员操作不熟练
D.装药量及装药结构不合理
E.爆破网路连接不规范
参考答案:A, B, D, E
Direct association of language with ______and persons of the immediate environment is emphasized in the Direct Method.
粉尘能致人体哪些疾患?