lostadj.迷路的；丢失的；错过的；失败的；不知所措的；摧毁的；被杀死的；忘我的；不能理解的动词lose的过去式和过去分词形式lost call未接通的呼叫

1. My sister sat silent for some time, lost in thought.
   我姐姐沉默地坐了一会儿，陷入沉思。
2. She heaved a sigh and became lost in thought.
   她叹了口气，随即陷入了沉思。