free on train

例句：

1. 1. She wasfree on the train to go home.
   她在火车上自由地回家。
2. 2. Thetrain is free on Sundays.
   火车在星期天是免费的。
3. 3. He was free on the train tovisit his friend in another city.
   他在火车上自由地去拜访他的朋友，住在另一个城市。