at one's best   (TTS發音)

in one's best state在最佳狀態；在全盛時期

    He is at his best with friends. 他同朋友們在一起時最開心。

    The peach blossoms are at their best now. 桃花正在盛開。

    She is at her best in the morning. 她早上情緒最佳。