If you ruminate on something, you think about it very carefully. [V on/about/over n] [Also V] [Formal]
He ruminated on the terrible wastage that typified American life…
他认真地考虑了美国生活中典型的严重浪费问题。
Obsessional personalities commonly ruminate excessively about death.
有强迫症的人通常过多地思考死亡的问题。