溶洞的英文：
karst cave

参考例句：

There are karst caves in Guilin
桂林有溶洞。

karst是什么意思：
n. 喀斯特（岩溶的旧称）

These outstanding examples of cone karst owe their existence and uniqueness to several interacting geological, biological, erosional and climatic phenomena.
这些极具特色的圆锥形喀斯特山峦，是由亿万年来地质、物或风化侵蚀作用与气候变化等诸多因素之间复杂的相互影响而形成的。

Jiuzhaigou Valley is known for its gorgeous karst land forms and spectacular waterfalls and lakes, a place recognized as Heaven on earth.
九寨沟因其壮观的卡斯特地貌、瀑布及湖水闻名，被誉为人间天堂。

We use land value, land rent, boundary avail value etc as the basic theories to count the value of karst tourist resources.
我们以地产价值、地租、边际效用价值等理论作为喀斯特旅游资源的价值核算的理论基础。

cave是什么意思：
n. 洞穴，地窖
v. （使）凹陷，塌落；在…挖洞穴；投降

They found a refuge in a cave.
他们避难于一个山洞中。

The guide flashed a light into the cave.
导游用手电筒照射洞穴。

The cave roof collapsed.
洞顶坍塌了。

They had at last to cave in and surrender.
他们最后不得不屈服投降。

He likes to explore the cave.
他喜欢在山洞里探险。