Thai is a verb-oriented language, often using verbs where English uses nouns (18.104.22.168) or prepositions. Verbs have a single form: they are not inflected for number or tense. Thus bpai can mean ‘go’, ‘went’, ‘will go’, etc.; ambiguity can be avoided by the addition of time expressions, such as ‘yesterday’, ‘next week’, etc., or auxiliary verbs and particles (5.3), but often the context alone is sufficient to clarify the situation. A common feature of Thai is verb serialisation (5.13).