lost in thought

• adj. 沉思(神往；呆呆地想着)

lost in thought的用法和样例：

例句

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。