professional proficiency

例句：

1. 1.He is a professional in the field of finance.
   他在金融领域是个专业人士。
2. 2. She is a professional in her field and has won many awards.
   她在她领域里是个专业人士，并赢得了许多奖项。
3. 3. The company needs a professional to help them with their marketing strategy.
   公司需要一位专业人士来帮助他们制定市场营销策略。