Although moral literature theory has its stable linguistic signification and definite form of genealogy of knowledge from ancient times to the present,it also has serious linguistic errors in the linguistic signific.

Equivalence proving of operational and denotational semantics about Repeat-until statement;

The static and dy-namic denotational semantics of Smalltalk-80 are described through the formal model.

The fixed point of continuous function is an important content in denotational semantics,which specifies the computing properties of programs.

This thesis analyzes the different functions of deixis and non-deixis in speech communication,gives a definition to the phenomenon,tries to explain it from accessibility theory,and finally points out that pre-emptiveness results from different accessibility of deixis psychologically.

This paper attempts to probe the flexibility from six aspects: context, deixis, conversational implication, pre-supposition, speech action, and conversational structure.