ebb

退潮时，沙滩上露出了许多贝壳。

Many seashells were exposed on the beach during the ___ebb tide.

随着季节的变化，游客数量开始逐渐减少。

As the season changed, the number of tourists began to ___ebb.

面试小组每提出一个他答不上的问题，他的自信就减退一分。

His confidence ___ebbed with each unanswered question from the interview panel.