单项选择题
VRML is a（1）for 3D multimedia and shared virtual worlds on the WWW.In comparison to HTML, VRML adds the next level of interaction,structured graphics,andextra（2）（z and time）to the presentation of documents.The applications of VRMLare（3）,ranging from simple business graphics to entertaining WWW page graphics, manufacturing,scientific,entertainment,and educational applications,and 3D shared virtual worlds and communities. X3D is the name under wluch the development of VRML is continueD.X3D is based on XML andis backwards（4）with VRML.Furthermore,it is componentized,profiled, and extensible,which makes it possible to use X3D in very different（5）,from high-end visualizations to lightweight applications.
单项选择题为了直观地分析系统的动作，从特定的视点出发描述系统的行为，需要采用动态分析的方法。其中（1）本来是表达异步系统的控制规则的图形表示方法，现在已经广泛地应用于硬件与软件系统的开发中，它适用于描述与分析相互独立、协同操作的处理系统，也就是并发执行的处理系统。（2）是描述系统的状态如何响应外部的信号进行推移的一种图形表示。
