The paper revisits Duffield’s (2007) (Duffield, Nigel. 2007. Aspects of Vietnamese clausal structure: Separating tense from assertion. Linguistics 45(4). 765–814) analysis of the correlation between the position of a ‘when’-phrase and the temporal reference of a bare sentence in Vietnamese. Bare sentences in Vietnamese, based on (Smith, Carlota S. & Mary S. Erbaugh. 2005. Temporal interpretation in Mandarin Chinese. Linguistics 43(4). 713–756), are argued to obtain their temporal interpretation from their aspectual composition, and the default temporal reference: bounded events are located in the past, unbounded events at present. It is shown that the correlation so observed in when-questions is superficial, and is tied to the syntax and semantics of temporal modification and the requirement that temporal adverbials denoting future time is base generated in sentence-initial position, and past time adverbials in sentence-final position. A ‘when’-phrase, being temporally underspecified, obtains its temporal value from its base position. However, the correlation between word order and temporal reference in argument wh-questions and declaratives is factual, depending on whether the predicate-argument configuration allows for a telic interpretation or not. To be specific, it is dependent on whether the application of Generic Modification (Snyder, William. 2012. Parameter theory and motion predicates. In Violeta Demonte & Louise McNally (eds.), Telicity, change, and state. Acrosscategorial view of event structure , 279–299. Oxford: Oxford University Press) or accomplishment composition is realized. Canonical declaratives, and argument wh-questions, with telicity inducing material, license GM or accomplishment composition, yielding bounded events, hence past; by contrast, their non-canonical counterparts block GM or accomplishment composition, giving rise to unbounded event descriptions, hence non-past.