1.如果单独使用,两个意思一样
2.连在一起使用,with是同谁一起打,against是同谁打
1.如:
Have you been fighting with (ie against) your brother again?
你又跟弟弟打架了吧?(ie=即)
2.如:
Britain fought with (ie as an ally of) France against Germany in the last war.在第二次世界大战中,英国与法国联合作战抗击德国.
也就是说fight with比against多一个并肩作战的意思:)