Fluorid
n. 氟化物
🗣️ 情景例句
and giving up your free time.
放弃了你的闲暇时间。
John stopped to study.
约翰停下来去学习。
In this part of the cave, they could hear an insistent booming sound which they found was caused by a small waterspout shooting down into a pool from the roof of the cave.
在这儿，他们可以听见一种连续不断的轰鸣声。后来他们发现这是由山洞顶部的一个小孔里喷出的水柱跌落到水潭中发出的声音。