Learners have to integrate their understanding of the grammar of English into a coherent system.
In order to do this we need to give them opportunities to practice grammar which they have been introduced to through meaning progressions.
For example, we might have nothing planned for this weekend so we can think through our options in a progression from a discussion of the potential available to us, to the decision, to the plan..
‘At the weekend I could do X, Y or Z.’
The modal verbs can and could are used to talk about potential:
It can rain a lot here in summer.
This does not mean that it does rain a lot or it will rain a lot. just that the potential is there.
I can speak French.
This does not mean I like speaking French, or I ever do speak french, just that if the need arises I am able to speak French.
‘If I do X, I could/would/might……..’
‘If I do Y, I could/would/might……..’
‘If I do Z, I could/would/might……..’
‘Ok, I will do X.’
The modal verb will expresses the speaker’s certainty, which is why we can use it to make decisions.
Once Decided, it is now a Plan
‘At the weekend, I’m going to do X.’
Once something is decided it can be talked about using ‘going to do’ as the process has begun. We are moving through time towards the event or action. All this, from the decision time to the actual event is conceptualized in this planning frame of going to do something.
Practicing the Sequence
All the above grammatical structures should be practiced in such a sequence so that the learners understand that, as the situation unfolds, different grammatical forms have their role to play in a coherent system of meaning.
For more ideas about the meanings of English grammar, please consider buying The Ideas of English Grammar.