cave in 1. 塌落，倒坍；(墙等)内陷；(由于疲劳等)垮下来 a caved-in roof 坍塌的屋顶 His face caved in. 他的脸瘦得出现了凹陷。 You need to go to sleep. You look ready to cave in. 你需要睡觉。你看上去随时可能垮下来。 2. 使塌落，使倒坍；使内陷 cave in a dike 使堤坝坍塌 a car with its fenders caved in 挡泥板撞得内陷的汽车 3. 〈口〉屈服，投降 cave in to an ultimatum 屈服于最后通牒 cave in before superior arguments 在更有力的论据面前屈服