When learning their first language, children develop strategies for assigning semantic roles to sentence structures, depending on morphosyntactic cues such as case and word order. Traditionally, comprehension experiments have presented transitive clauses in isolation, and cross-linguistically children have been found to misinterpret object-first constructions by following a word-order strategy (Chan, Lieven & Tomasello, 2009; Dittmar, Abbot-Smith, Lieven & Tomasello, 2008; Hakuta, 1982; McDonald, 1989; Slobin & Bever, 1982). In an act-out study, we replicated this finding with Danish preschoolers. However, object-first clauses may be context-sensitive structures, which are infelicitous in isolation. In a second act-out study we presented OVS clauses in supportive and unsupportive discourse contexts and in isolation and found that five- to six-year-olds' OVS comprehension was enhanced in discourse-pragmatically felicitous contexts. Our results extend previous findings of preschoolers' sensitivity to discourse-contextual cues in sentence comprehension (Hurewitz, 2001; Song & Fisher, 2005) to the basic task of assigning agent and patient roles.