A standard one. Replacement during the first year if all rules for proper use have been followed.
有一个原则,如果在一年内符合各种使用规定,就可更换。
It can take as long as eight days to rig up rope ladders and to establish supply bases before a descent can be made into a very deep cave.
有时需要花费整整8天时间来搭起绳梯,建立供应基地,然后才能到一个很深的洞穴里。