他咬了咬嘴唇，显得很紧张。

He bit his lip, looking very nervous.

她有一个紧张时咬嘴唇的习惯。

She has a habit of biting her lips when she is nervous.

她在思考问题时无意识地咬了咬嘴唇。

She unconsciously bit her lip while thinking about the problem.

他咬了咬嘴唇，不置可否。

He pursed his lips noncommittally.

乔布斯咬了咬嘴唇，调整了一下金丝镜架，换上一副优雅而谦卑的面孔。

Jobs bit his lip, adjusted his wire rims, and put on a graceful show of humility.

不断地咬嘴唇内部，寡合得仿佛处身愁茧，默无一言。

He kept chewing the inside of his lip a lot, frozen into some personal cocoon of silence.

梅埋下头, 她咬了咬嘴唇皮, 额上的皱纹显得更深了.

Mei did not weep. She only bit her lips, and the furrow in her brow deepened.