Modality is a grammatical, or semantic-grammatical, category. It is an important component of human languages. This is at least the case in most European languages. To what extent is it a near-universal? This thesis is to contribute to the question. It focuses on modal verbs in English and Chinese, two genetically and geographically unrelated languages, and analyzes what these two languages have in common and how they differ in their systems of modality. To achieve the aim, the thesis adopts the theoretical framework proposed by van der Auwera (1996, 1998 with Plungian, 2001) for the...