Suddenly they came to a waterfall which dropped into an underground lake at the bottom of the cave.
突然，他们来到一道瀑布前，那瀑布奔泻而下，注入洞底一处地下湖里。
新概念英语第三册
Lesson 42 Modern cavemen
📚 句中词汇解析
从本句中提取的重要词汇
adv. 意外地，忽然地;奄;勃;霍然;
💡 sudden突然的 + ly ...地 → adv.突然地
"Suddenly he found himself awake and fully alert."
突然他发觉自己醒了过来，而且高度警觉。
近义：impromptu, inadvertently, abruptly, offhand, overnight, sharply
反义：progressively, slowly, sparingly, stingily, inchmeal, consecutively
n. 瀑布;瀑布似的东西;<美俚>（披垂的）波型长发;
💡 water水+fall落下 → 瀑布
"A cloud of fine spray came up from the waterfall."
飞瀑溅起一片水雾。
近义：cascade, cataract, chute, fall
adj. 地下的;秘密的;先锋派的;隐蔽的;
💡 under在…下+ground地→地下的
"a secret underground passage"
地下秘密通道
近义：subsurface, subterranean, subterraneous, buried, backdoor, secret
反义：jural, lawful, legit, legitimate, licit, original
n. 洞穴;〈方〉地窖;
vt.& vi. （使）塌陷，倒塌;暗中破坏;
vi. 屈服;
💡 cav洞+e → 山洞，洞穴，窑洞
"a dark dank cave"
阴暗潮湿的洞穴
近义：dig, excavate, cavern, crypt, den, dugout
n. 湖;深红色颜料;胭脂红;[化]色淀;
vt.&vi. 血球溶解;使（血液）发生血球溶解;
"Fish are abundant in the lake."
湖里鱼很多。
近义：lagoon, loch, lacustrine