a class of complex mapping的用法和样例：
- Pele was in a class of his own as a footballer.
- It's no easy task to take control of a class of young children.
- The purpose of this paper is to investigated the problem of the behaviour of meromorphic solutions of a class of complex differential Equations and to generalize Theorem A to higherr-order equation.
- A class of people regarded as stupid and gullible.
- She taught a class of 30 pupils.