Time Phase Of Attribution: Tense

Halliday & Matthiessen (2004: 222-3):

When it is specified for time, the tense may be like that of ‘material’ clauses rather than like that of ‘relational’ ones … That is, coming into being is construed on the same model as activities, as far as time is concerned; but it is still construed as a configuration of being …

Phase Of Attribution: Neutral Or Phased

Halliday & Matthiessen (2004: 222):

Like other processes, processes of attribution unfold through time. In the unmarked case, the phase of the unfolding is left unspecified (‘neutral’); alternatively, it is specified in terms of time, appearance or sense–perception …