This paper describes some operational aspects of a language comprehension model which unifies the linguistic theory and the semantic theory in respect to operations. The computational model, called Augmented Dependency Grammar (ADG), formulates not only the linguistic dependency structure of sentences but also the semantic dependency structure using the extended deep case grammar and field-oriented fact-knowledge based inferences. Fact knowledge base and ADG model clarify the qualitative difference between what we call semantics and logical meaning. From a practical view point, it provides clear image of syntactic/semantic computation for language processing in analysis and synthesis. It also explains the gap in semantics and logical meaning, and gives a clear computational image of what we call conceptual analysis.This grammar is used for analysis of Japanese and synthesis of English, in the Japanese-to-English machine translation system called VENUS (Vehicle for Natural Language Understanding and Synthesis) currently developed by NEC.