A number of recent studies on tense in L2 have claimed that the past tense is acquired in developmental stages: verbs, such as 'build' and 'work,' which are lexico-aspectually more event-like (less state-like) are claimed to be marked for past tense earlier in the developmental process than those, such as 'be' and 'want,' which are less event-like (more state-like). In this paper, I will closely examine seven samples of writing by L1 speakers of Vietnamese to show that grounding, rather than lexical aspect, properly accounts for the selective marking of past tense. I will suggest that the learner-hypothesis that governs this use of English past tense derives from the transference of a grounding-marking principle from a tense-free language, and I will briefly address the pedagogical implications of this finding.