Grammar is meant for communication and grammar has to make sense! The Chinese grammar is featured by its form-function mapping principles that are crucial in understanding the unique “character” of Chinese. This study aims to explore the form-meaning mapping relations behind three commonly used function words, the pre-nominal DE (的), the post-verbal DE (得), and the default degree marker HEN (很).The three function words are re-defined by associating their relatively-fixed formal properties with their prototypical functions. The pre-nominal DE is used as a marker of pre-Head modification or specification, which is presuppositional in nature; the post-verbal DE marks a post-verbal complement by affixing to the verb; the degree marker HEN is a signal or trigger of evaluative predication. The proposed analyses are able to account for the various uses of the three markers and find answers to previously puzzling questions. The study shows that a function-based approach to Chinese grammar may help delimit the core grammatical roles of the three markers and explain their diverse uses and constraints in a well-motivated manner.