a knowing smile的用法和样例：
- His face crease in a knowing smile.
- She accompanied the words with a knowing smile.
- When visitors do cross paths, the exchange is often marked with a knowing smile, a wry bewilderment.And also a sense of wonder.
- Oboi stood there watching and chuckling to himself.He could see that the eunuchs were not particularly skilful, and shook his head with a knowing smile.
- He is “taken” in all senses by a knowing nymphet.