Tom found a subterranean lake, shortly, which stretched its dim length away until its shape was lost in the shadows.
汤姆很快就发现了一个地下湖,它把它昏暗的长度拉长,直到它的形状消失在阴影中。
英语百科
Underground lake
(重定向自Subterranean lake)
An underground lake or a subterranean lake is a lake under the surface of the Earth. Such a lake may be associated with caves, aquifers, or springs. They are typically very low in salinity.
The largest non-subglacial underground lake in the world is Dragon's Breath Cave, Namibia, with an area of almost 2 hectares (5 acres) and the second largest is Craighead Caverns in Tennessee, United States of America.