Modal adverbs are special grammatical constituents,and are always associated with pragmatic factors.

It studies how the pragmatic factors, such as communicative intention, context, pragmatic presupposition, influence and constrain the choice and use of syntactic structures, and how they cause the unmarked clauses to change into marked ones.

First, we make deep research on the speech act of gratitude in modern Chinese, include its definition, structure patters, strategies types and the effect of pragmatic factors.

It holds that RRG is a powerful grammar as it successfully incorporates discourse and pragmatic factors into the syntactic analysis,and it can not only interpret the structural features of hypotaxical languages like English,but is also suitable for the structural.

The present paper offers a tentative analysis of the corresponding relationship between the construction of interrogative sentences and the related pragmatic factors such as uncertainty,expectation,sincerity and politeness in line with the principle of iconicity,so that a complete understanding of the grammatical relation of interrogative sentences can be acquired.

Based on the restrictive role of pragmatic elements in Chinese sentence structure,this paper explores how teachers should make more appropriate use of pragmatic knowledge in teaching Chinese to foreign students in the five following aspects:pragmatic elements,interference of context,focus on topics,central issues and new or old information,pragmatic word order and dialogue analysis.