stochastic Petri nets

例句：

1. 1. The probability of rain is stochastic, meaning it depends on the weather conditions.
   下雨的概率是随机的，意味着它取决于天气条件。
2. 2. In statistics, stochastic processes are those that can be modeled as random events.
   在统计学中，随机过程是可以建模为随机事件的那些过程。
3. 3. The results of a stochastic simulation are often unpredictable and difficult to analyze.
   随机模拟的结果往往是不可预测的，难以分析。