阅读短文，从方框中选择适当的单词填空 (每词限用一次)。

population     dream      is      of     so     

Changqing has a long history but it is the new district of Jinan. It 小题1:_________ in the west of Jinan. and covers 1178 square kilometers. The 小题2:_________ of Changqing is about 530,000. It has convenient transportation 小题3:_________ it’s easy to get here. There are many ancient places of interest for you to visit, such as Lingyan Temple, Xiaotang Hill and so on. It has changed a lot since it became the new district of Jinan. Now it has 15 colleges or universities. You can make your 小题4:________come true there. And the Expo garden which was built newly attracts thousands小题5:_________visitors every year. Welcome to Changqing, and you will enjoy yourself.

螺旋模型是一种演进式的软件过程模型，结合了原型开发方法的系统性和瀑布模型可控性特点。它有两个显著特点，一是采用（）的方式逐步加深系统定义和实现的深度，降低风险；二是确定一系列（），确保项目开发过程中的相关利益者都支持可行的和令人满意的系统解决方案。

A．实现方案

B．设计方案

C．关键点

D．里程碑