短语 “grin from ear to ear” 或者 “smile from ear to ear” 用来描述某人 “开心地咧嘴大笑，笑得合不拢嘴”。

• When I got my exam results, I was grinning from ear to ear.
  当我拿到考试成绩时，我开心极了，笑得合不拢嘴。
• I grinned from ear to ear when I heard about my promotion.
  听到升职的消息，我笑开了花。
• It was his birthday, so no wonder he was grinning from ear to ear!
  那天是他的生日，怪不得他当时咧着嘴笑得那么开心。