The symbols and time durations for different transitions and places are shown in Table 2.1.不同转变和地点的符号和延续时间见表2.1 Table 2.1.The time durations associated with transitions and places 表2.1 与转变和地点相关的延续时间 Time duration：持续时间,延续时间
The symbols and time durations for different transitions and places are shown in Table 2.1.不同转变和地点的符号和延续时间见表2.1 Table 2.1.The time durations associated with transitions and places 表2.1 与转变和地点相关的延续时间 Time duration：持续时间,延续时间