这个过程中最关键的一步应该是随着海浪的冲击悬崖的后退，因为海水最先能够

This process is the most critical step should be back with the shock waves of the cliff, because the water is the first to be able to attack the bottom of the cliff, and so the bottom of the cliff depression to a certain extent, you can take advantage of sea erosion up, prompting the upper end of the cliff the surface portion of the retreat

The most critical step in this process should be as the waves hit the cliff retreat, because the first thing the sea can be able to erode is the bottom of the cliff, and when the bottom of the cliff is sunken to a certain extent, the sea can erode upward, causing the upper part of the cliff to retreat

The most critical step in this process should be the retreat of the cliff with the impact of the waves, because the bottom of the cliff is the first thing that can be eroded by the sea water. When the bottom of the cliff is depressed to a certain extent, the sea water can be eroded upward to make the surface part of the top of the cliff retreat