1, In this paper , we study a nonautonomous SIS model with age structure.

2, A three species predator prey chain periodic nonautonomous diffusive system is studied.

3, The fundamental response of a nonlinear nonautonomous system is periodic, quasi - periodic and chaotic motion.

4, In a nonautonomous system, f is explicitly a function of t.

5, We discuss uniform extremely stable and uniform distances boundedness of solutions of nonautonomous equations.

6, Above method can be applied to both autonomous system and nonautonomous system.

7, This paper is to consider subharmornic solutions for a class of nonautonomous second order systems.