I must learn to bite my lip.

我必须学会不随便说话。

《柯林斯英汉双解大词典》

Something tickled my hindbrain then, and I had to bite my lip to keep from laughing.

就在此时，不知什么东西挠了下我的后脑，我使劲咬住嘴唇才没有笑出来。

youdao

His piercing blue eyes and messy dark hair made me bite the inside of my lip.

看到他那打动人心的蓝眼睛和凌乱的黑发，我咬了咬自己的嘴唇。

youdao

Do I speak my mind or bite my lip, lest I ruffle feathers or subject myself to criticism?

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