n.钟乳石
Not every stalactite has a complementary stalagmite. 不是每根钟乳石都有互生的石笋。
You can calculate, how long will it take for the stalactite of such type to grow. 请诸位算一算，这么大的钟乳石得需要多少个漫长的岁月啊！
n.石钟乳
