请列举五个历史战役，并按时间顺序排列，要求每个战役名称后附年份和交战方，以JSON格式输出
user
```json
{
  "battles": [
    {
      "name": "长平之战",
      "year": "260 BC",
      "opponents": "秦国 vs 赵国"
    },
    {
      "name": "赤壁之战",
      "year": "208 AD",
      "opponents": "东吴 & 蜀汉 vs 曹魏"
    },
    {
      "name": "淝水之战",
      "year": "383 AD",
      "opponents": "东晋 vs 前秦"
    },
    {
      "name": "诺曼底登陆",
      "year": "1944",
      "opponents": "盟军 vs 纳粹德国"
    },
    {
      "name": "海湾战争",
      "year": "1991",
      "opponents": "多国联军 vs 伊拉克"
    }
  ]
}
```
assistant