一个动作典型地导致系统状态的变化，并且能通过给一个对象发送消息或者通过修改一个链接和属性值而实现。

An action typically results in a change in the state of the system, and can be realized by sending a message to an object or modifying a link or a value of an attribute.

youdao

一个动作典型地导致系统状态的变化，并且能通过给一个对象发送消息或者通过修改一个链接和属性值而实现。

An action typically results in a change in the state of the system, and can be realized by sending a message to an object or modifying a link or a value of an attribute.

youdao