Usually when teaching tenses for EFL classes we focus on time as the key element that differentiates each one. We compare simple and continuous in terms of ‘usually’ and ‘now’. Recently, however, I’ve been trying to take a more discourse approach to tenses by focusing on why each tense is selected a text and, rather than just comparing present simple and continuous tenses (aspect really), Halliday’s notion of Primary and Secondary tenses is more useful. A good way to do this is with sports commentary.
Ideationally, sports commentary really has two main focii: the game as a whole and the participants in it. Interpersonally, we also need to distinguish between describing the game and commenting (offering opinions) on it. Often, these are distinguished through varying Primary and Secondary tenses.
For example, in football the main focus of describing the game is on the ball – he gathers the ball, threads a pass through, shoots and scores! – and here the Primary present tense is used. When switching the focus to the teams and comment, on the other hand, the Secondary present-in-present or past-in-present tenses are more commonly used – Liverpool are playing particularly well here, they have shut done the Manchester attack all night – while the players often need a further level of delicacy to a present-in-past-in-present – Gerrard has been playing particularly well. The choice of tense then reflects not so much the passage of time of the game but the focus of discourse about the game.