a class advisor的用法和样例：
- Pele was in a class of his own as a footballer.
- He is not so sick but he can attend a class.
- Her mother's cakes are in a class by themselves.
- Her mother's hair-style is in a class by itself.
- It's no easy task to take control of a class of young children.
- A class of people regarded as stupid and gullible.