快速应用开发（Rapid Application Development，RAD）通过使用基于（1）的开发方法获得快速开发。当（2）时，最适合于采用RAD方法。
空白（1）处应选择（）
Rapid application development (RAD) systems purport to lighten the developer’s (46) by making it easy to program an application with simple intuitive steps.
RAD tools (47) the developer everything needed to construct a fully functional application quickly and easily. They make short work of modifying the developed product to (48) changes after the program is finished. Applications developed with RAD tools are constructed as they are envisioned. As an application’s real usefulness (49) , the developer armed with RAD tools should be able to (50) on new features with little fuss.
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