light up
⇒ 老人一见到孙子就喜笑颜开的。
As soon as the old man sees his grandchild his face lights up.
英语词典包含298861条英英释义在线翻译词条，基本涵盖了全部常用单词的英英翻译及用法，是英语学习的有利工具。