Abstract:

The wide use of modal verbs in business contracts can improve the fluency of expression and ensure its validity and accuracy. Thus, the proper use of modal verbs can facilitate the emotional expression，transfer information and enhance successful communication. On one hand, based on the theoretical framework of systemic-functional grammar put forward by Halliday (1985), this thesis analyzes the modal verbs used in 30 authentic business contracts by employing both quantitative and qualitative methods, and explores the interpersonal functions expressed by these modal verbs. It aims at finding out why modal verbs are used and how they are used in business contracts to realize interpersonal functions. On the other hand, based on the Speech Act Theory, this thesis deeply explores the pragmatic functions and different illocutionary acts by expounding the pragmatic functions of modal verbs in business contracts. Modal verbs can help express the speaker’s views and attitudes. It has a guiding sense to express emotions, transfer information, facilitate communication, and avoid pragmatic errors by understanding the semantic and pragmatic functions of modal verbs in business contracts. In order to understand the functions of modal verbs, it is necessary to expound and analyze their functions by combining many cases and translations, finding the distribution regularities and usage characteristics of core modal verbs, thus reveal the importance of modal verbs to business contracts.

Key words: English business contract; modal verb; interpersonal function; pragmatic function,

摘要：

情态动词在商务合同中的广泛使用不仅使语言表达变得更灵活，又确保了合同的有效性和准确性。因此，正确使用情态动词有利于恰当地表达情感，传递信息和促进交际的成功。其一，以韩礼德在1985年提出的系统功能语法为理论框架，以30篇真实的合同文本为分析对象，本论文通过定量和定性两种方法分析商务合同中情态动词的使用，探索其所表达的人际功能意义。本文主要研究了商务合同中的情态动词的使用以及如何实现人际功能意义，以期帮助合同双方准确的理解合同所表达的法律效力。其二，以言语行为理论为理论框架，本文从阐述情态动词在商务合同中的语义功能出发，深入探究了他们的语用功能，不同的言外行为。情态动词是可以表达说话者看法和态度的用词。明确情态动词在商务合同中的语义及语用功能对于表达情感，传递信息，促成交际及避免语用错误都具有一定的指导意义。为了理解情态动词在商务合同中的功能，有必要结合诸多案例和翻译进行阐述和分析，寻找核心情态动词的分布规律和使用特点，并由此揭示情态动词对于商务合同的重要性。

关键词：商务英语合同；情态动词；人际功能；语用功能

Introduction
With China's entry into the WTO and rapid growth of its economic strength, there are more and more opportunities for Chinese enterprises to participate in the international market. Therefore, in order to direct and guarantee the transaction and business cooperation, business contracts, as an important form of communication, are supposed to be drafted and signed by the relative parties after negotiation.
However, globalization brings about not only opportunities, but also a lot of challenges. Due to the differences in cultures, legal systems and economic interests, international trade disputes frequently occur between China and other countries. So, it is necessary to accurately stipulate obligations and rights and other essential terms like payment, compensation, etc. in business contracts. In the same way, a better understanding of business contracts plays a vital role in protecting one's interests. Business contracts, especially international business contracts, serve significant functions in economy.