Present tense assigns a value to the designated element in the clause when the meaning selected for the clause is that intended to locate the event spoken about as simultaneous to the deictic centre of the utterance.
The simultaneous temporal relation may obtain either in 'simple' or 'perfect' contexts. Modelling of this distinction originates from [Reichenbach 1947: 288], who suggested using a third point in time, 'reference point', to capture all possible tense distinctions. In all 'simple' temporal relations, the reference point coincides with the location of the event spoken about. [Kibort 2008c: 4-5]