n. a geological formation consisting of an underground enclosure with access from the surface of the ground or from the sea
v. hollow out as if making a cave or opening
v. explore natural caves
n. 洞, 穴
vi. 凹陷, 塌落
vt. 挖洞, 使凹陷, 损坏...的基础
1. The explorers found a hidden cave in the mountains.
探险者在山中发现了一个隐藏的洞穴。
2. Bats often live in dark caves.
蝙蝠通常生活在黑暗的洞穴里。
3. We went hiking and discovered a beautiful cave by the river.
我们去远足，发现了河边一个美丽的洞穴。