1. 落潮 , 退潮

2. 衰退 , 衰落 [(+away)] Our hope of winning began to ebb in the third round. 比赛进入第三回合时我们打赢的希望变得渺茫了。

1. 落潮 , 退潮 They started sailing on the ebb . 他们于退潮时出航了。

2. 衰退 , 衰落 The scandal brought his credibility to its lowest ebb . 那件丑闻使他的信誉跌到最低点。