Baraba′si has proposed a queue model of the human behavior. In this paper we compare the Baraba′si results and Va′zquez results.　We proposed a model of human behavior dynamics by taking into consideration the service-time distribution. We obtained exact results for the model by calculating the waiting time distribution and sojourn time distribution of active tasks. The results show that the waiting time distribution of the model is a power-law distribution with exponent 2 for the highest priority first selection protocol. This exponent approximates to degree exponent 2.1 observed in Hsue-Shen Tsien correspondence pattern.