Introduction 3

1. Category of linguistic modality 4

1.1 Expression 5

1.2 Types 6

1.2.1 Epistemic modality 6

1.2.2 Deontic 6

1.2.3 Propositional attitudes 7

1.2.4 Possible worlds 8

1.2.5 Epistemic modality and evidentiality 8

2. English modal verb 10

2.1 Function 10

2.2 List 11

2.3 Properties 12

2.4 The meanings of modal verbs 14

2.5 Synonyms 15

2.6 Substitutes 15

3. Modal verbs detailed description 17

Conclusions 26

Literature 27