海岸线正被缓慢侵蚀。

The coastline is slowly being ___eroded.

深邃的峡谷是经过数百万年被水流侵蚀形成的。

The deep canyon was ___eroded by water over millions of years.

暴雨能迅速侵蚀河岸。

Heavy rains can quickly ___erode the banks of a river.