两支军队在平原上激烈交战了三天。

The two armies ___battled fiercely on the plain for three days.

两位候选人在辩论中激烈交锋。

The two candidates ___battled fiercely during the debate.

他多年来一直与贫困作斗争，最终改善了生活条件。

He ___battled against poverty for years before finally improving his living conditions.