For nearly ten years, the Unified Modeling Language (UML) has been the industry standard for visualizing, specifying, constructing, and documenting the （）of a software-intensive system. As the（）standard modeling language, the UML facilitates communication and reduces confusion among project（）. The recent standardization of UML 2.0 has further extended the language’s scope and viability. Its inherent expressiveness allows users to（）everything from enterprise information systems and distributed Web-based applications to real-time embedded systems.

The UML is not limited to modeling software. In fact, it is expressive enough to model（）systems, such as workflow in the legal system, the structure and behavior of a patient healthcare system, software engineering in aircraft combat systems, and the design of hardware.

To understand the UML, you need to form a conceptual model of the language, and this requires learning three major elements: the UML’s basic building blocks, the rules that dictate how those building blocks may be put together, and some common mechanisms that apply throughout the UML.

and documenting the （）of a software-intensive system

A．classes

B．components

C．sequences

D．artifacts

患者女，23岁。凹面型，面下1／3正常，前牙反牙合，磨牙中性关系，上颌尖牙唇向高位，拥挤9mm。上下前牙唇倾度正常，下牙列无拥挤。侧位片测量显示上颌骨发育不足，ANB-2°。4个第三磨牙牙胚存在 。

若该患者确定是固定正畸治疗，治疗方案可能为下列哪项 （）

A.不拔牙矫治

B.拔除2个上颌双尖牙

C.拔除4个第一双尖牙

D.拔除双侧上颌第二双尖牙和下颌第一双尖牙

E.拔除4个第二双尖牙