MI粒度更大，代表活动，而方法是事物自身一种能力体现，比如足球比赛是一个活动，需要参与人员有踢球能力，也就是踢球的方法。

行为动词的粒度比较：

方法-->交互-->活动

一个活动由一系列交互组成，一个交互是两个对象对方法的调用，至少涉及到两个方法。

交互经常用消息或事件代表。

1st - Is it a moment in or interval of time, something the system needs to

track for business or for legal reasons? If so, it's a pink momentinterval.

2nd – Otherwise, is it a role? If so, it's a yellow role.

3rd – Otherwise, is it a catalog-like description, a grouping of values that

you can apply again and again? If so, it's blue description.

4th - Otherwise, it's a party, place or thing. It's a green party, place, or

thing (green is the default; if not pink yellow, or blue, it's green).

我的经验是按照名词动词法则，见：动词是个独裁者，MI一般是动词，其他三个是名词。

MI代表业务活动，与时间有关的连续活动。