but it's a tricky place to take your first steps. 但第一次踏出脚时是不能掉以轻心的

179. They are just two months old
     小熊才两个月大
180. and instinctively follow her lead.
     本能地跟在母亲后面
181. A steep slope makes the best site for a den,
     陡峭的斜坡是穴居的好地点
182. but it's a tricky place to take your first steps.
     但第一次踏出脚时是不能掉以轻心的
183. It may look like fun but this is serious training for the task ahead.
     可能看起来很好玩, 但这都是为马上来临的严峻挑战所做的训练
184. There is no food on the slopes
     山坡上面没有食物
185. and the family will need to head out across the frozen sea before the mother's milk runs dry.
     在母熊奶水干涸之前 一家人需要穿越冰封的海洋

来自《行星地球 第一季 第六集 Planet Earth S01E06 冰雪世界》第 182 行