shí / huī / yán / shòu / dào / dì / xià / shuǐ / róng / shí / hòu / kě / néng / xíng / chéng / tiān / rán / róng / dòng

石灰岩受到地下水溶蚀后，可能形成天然溶洞。

After limestone is dissolved and eroded by groundwater, natural caves may form.