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.