expert on folklore

例句：

1. 1. She is an expert in the field of astronomy.
   她在天文学领域是一位专家。
2. 2. He is an expert in his field and has won many awards.
   他在自己的领域里是一位专家，并且获得了许多奖项。
3. 3. The expert gave us valuable advice on how to improve our work efficiency.
   这位专家给我们提供了关于如何提高工作效率的宝贵建议。