The end of 19th century witnessed occurrence of the term Presupposition in logics to discuss Meaning and Logics in a sentence,which makes the study more accurate.Until the end of 1970s had most studies on Presupposition been confined to a static sentence.Then Cognitive Science broadens the scope of study which transfered to Presupposition's cognitive laws and functions.Grounded on this trend,this paper,guided by The Cognitive View,explores the generation of cognitive text and develops a new explanation to the functions of textual presuppositions.This study urges a reflection upon the translation class,which at last leads to conceiving a new type of translation class by Situational Model(S.M.).It is a tribute to Translation Teaching and Presupposition Study.