This paper proposes a hypothesis for the interpretation of tense in English from the viewpoint of how the conception of time is reflected in linguistic temporal expressions. The hypothesis is then verified in light of acquisition data. The paper claims that following from the analysis of the conception of time in Section 2, three temporal entities, namely, speech time, event time, and cognition time, and either a simultaneous or an ordinal relation between two of them, should be posited as primitives. It is argued that if the cognizer and the speaker of the embedded proposition are taken into consideration, the interpretation of tense in embedded clauses naturally follows from the principles of simple sentences. Based on the proposed hypothesis for an adult's interpretation of tense, acquisition data on the deicitic use of past forms of an English-Japanese girl are analyzed. The implications the acquisition data have on the proposed and competing hypotheses for the interpretation of tense are discussed. Analysis is confined to the temporal relations, either simultaneous or anterior to the speech time. The posterior relations are not included because they involve the modal auxillary "will," and the question of whether a structure with "will" reflects only a temporal relation or the wider notion of possibility under which futurity may be subsumed is still open. (VWL)