隧道穿过松散地层,应减少对围岩的扰动,一般采取(),密闭支撑,边挖边封闭的施工原则。
参考答案:先护后挖
_____ the group guide, all teams have cookers and porters.
A.In addition
B.Due to
C.As well as
D.As well
AD199系列机型第一纸盒采用摩擦垫进纸系统。