Some of them have a very precarious thin footbridge underneath them that could give way at a moment's notice, taking your sled, you, into the abyss, never to be seen again.
有些裂缝的下面就是岌岌可危的薄天桥 这些可以给你一个大概的印象， 拽着雪橇，你，在深渊中，在也不会被别人看到。