grin like a cheshire cat爱丽丝在公爵家中看到一只会笑的猫，就问公爵夫人为什么这只猫一直在莫明其妙的咧嘴笑，夫人告诉她，那是一只“柴郡猫”，由此产生该语，后人就用它来喻指“咧嘴傻笑”。

【例句】
I wish you’d stop grinning like a Cheshire cat and try to be serious.
我希望你不要再傻笑了，要认真严肃些。

I like laughing while praised by teacher, teased by schoolmate, so much as criticized, I also grin like a Cheshire cat.
我还是个爱笑的女孩，得到老师表扬了笑；被同学欺负了笑；甚至挨了批评还是一副笑嘻嘻的表情。