?陷入沉思

这是个固定搭配，lost in thought （陷入沉思），永远这样用

?沉思

天无绝人之路 Lost in thought沉思 It came like a bolt from the blue这事情的发生就像晴天霹雳一样（a bolt from the blue晴天霹雳； blue 悲伤地；蓝颜色的bolt[...

?怔神儿

... 运神 to concentrate; to think what you're doing 怔神儿 lost in thought; in a daze 怔神儿 lost in thought; in a daze ...