Jill crossed her legs and rested her chin on one fist, as if lost in deep thought.

吉尔两腿交叉，下巴抵在拳头上，似乎陷入了沉思。

《柯林斯英汉双解大词典》

Lost in deep thought, I didn't hear the phone.

沉溺在深思中，我没听到电话声。

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The sudden knocking at the door startled me when I was lost in deep thought.

我正在沉思，突如其来的敲门吓了我一跳。

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