They clambered back under the falls to detach the raft from a jagged rock.
他们爬回到瀑布下面以便将卡在锯齿状岩石间的小艇拉出来。
《柯林斯英汉双解大词典》
2
The clear rock magnified the letters, making them appear larger, it's like what happens when a drop of water falls on something, whatever's below the drop of water appears larger, right?