主要参与者和次要参与者之间的区别在于，第一个参与者具有用例的目标，而第二个参与者需要完成该目标，但是第二个参与者在用例中没有目标.因此，这些定义是相互排斥的，主要参与者永远不会成为次要参与者.主要参与者能够在用例中执行操作.

The difference between a primary actor and the secondary actor is that the first one has a goal with the use case and the second one is needed to accomplish that, but the second actor does not have a goal within the use case. Therefor are those definitions mutually exclusive and can a primary actor never be a secondary actor. A primary actor is capable to execute actions within the use case.

同一个用户可以有不同的角色.对于某个用例，这些不同的角色可以是主要和次要角色.因此，在一个用例中，同一用户可以是主要参与者和次要参与者.但这并不意味着一个演员可以同时是主要和次要演员.

The same user can have different roles. Those different roles can be primary and secondary actor for a certain use case. Therefor can the same user be a primary and secondary actor in one use case. But that does not imply that one actor can be primary and secondary actor at the same time.