During one of these engagements, type hierarchies played a significant role in the solution, making us recognize that top-down development has some advantages over bottom-up development when inheritance is required.

• 在这些约定中,类型层次在解决方案中扮演了一个非常重要的角色,它使我们认识到当需要继承时,自顶向下开发要比自底向上开发更有优越性。