Here the strategy is to take little and often. 但在这里的饮水策略却是少而频繁
Cave exploration often requires you to push yourself through narrow gaps in the rock. 洞穴探险需要不时挤过 一些狭窄的岩石缝隙
often more than 60 metres from the floor. 通常高出地面60多米
Rivers that flow over limestone often seem to completely disappear. 流经石灰岩的河川 到最后似乎总是无影无踪