to ruminate on sth or to ruminate over sth or to ruminate about sth反复思考某事
He ruminated on the terrible wastage of consumerism.他反复考虑了消费主义带来的严重浪费问题。
He would ruminate excessively about death.关于死亡问题他往往思考过多。
The electorate ruminated over its choice of government.选民反复考虑了选择政体的问题。