/keɪv ||; kev/noun [C] a large hole in the side of a cliff or hill, or under the ground 山洞；地洞；洞穴: When it started to rain, we ran to shelter in a cave.雨下起来的时候，我们都跑进山洞里避雨。
cave²
/keɪv ||; kev/verbcave in
1 to fall in 塌落；坍塌；内陷: The roof of the tunnel had caved in and we could go no further.隧道顶部已塌陷，我们无法再前进。
2 to suddenly stop arguing or being against sth 屈服；妥协: He finally caved in and agreed to the plan.他终于软化，同意了这个计划。