Because system behavior is the result of objects sending messages to each other, sequence diagrams plot the course of those messages as they move from object to object.
因为系统行为是对象相互之间发送消息的结果，因此序列图绘制了那些消息在对象之间移动时的路线。
2
The plot defines the sequence of events that lead the protagonist to her objective.
故事情节规定了事件发生的顺序，引导故事主人公达到目的。
3
Once the plot function is called, you need to take the following steps, in sequence.