Our intuitive concept of force includes such ideas as placeofapplication, direction, and magnitude, and these are called the characteristics of a force.
力的直观概念包括力的作用点、大小、方向，这些被称为力的三要素。
2
As application architects, we use the use case model to identify the external boundaries of the application and the interactions that take place at those boundaries.
作为应用程序架构师，我们可以使用用例模型以确定应用程序的外部边界、以及在这些边界处的交互。
3
Most of the ingredients are in place to carry out a thorough problem analysis of a large application.