最佳答案：前面用介词at，例如：1.He was a statesmanand worked out many reforms for the state, like paying more attention
前面用介词at，例如：
1.He was a statesmanand worked out many reforms for the state, like paying more attention to farming and giving rewardsto soldiers who were successful when at war.他是一位政治家,为国家进行了许多改革,比如更加重视农业,奖励在战争中取得成功的士兵。
2.Technically, the two countries are still at war.严格说来，这两国仍在交战。
3.How long have they been at war?他们交战有多长时间了？
