I don’t write blog a long time .Maybe I forget it ,however ,I remember all time .Recently,I’m busy to writing documents about software such as requirement document ,detailed design documents ,summary of design documents and so on .but I can’t find my though ,I still have been in disarray,I don’t know how to start..but the teacher had said “I need you grows in mistake”but now the situation wasn’t change. Because I can’t write ,in particular,using rational rose drawn the class diagram.In my view ,painted a veriety of the diagams is a process to understand the engineering.let us understand the software engineering theory ,using the theory to creat your own software thinking.