题目对应音频为：So, this process shouldn’t be too hard to imagine. What happens is that the ice at the base of the glacier is under a great deal of pressure … this results in a thin layer of water between the glacier and the ground. This layer of water reduces friction is ... is like a lubricant. And it allows the glacier to slide or slip over the bedrock. 由此可知，先是冰川底部冰层受到压力，形成液体层，液体层使冰山和岩床间的摩擦力减小，从而造成冰川滑动，四个步骤对应选项为 D B A C。

答案: DBAC