A student the other day had difficulty with a textbook matching exercise. The prompt was:
Are you watching the TV?
The required option was:
You can turn it off.
I think the difficulty here was due to the incongruence of the lexico-grammar (present-in present material Process) with the Interpersonal semantics (a request to turn off the TV rather than a request for information). The exercise was ostensibly practising the present progressive but the student was confused as the expected response (‘Yes, I am watching the TV) did not appear.
I must admit I’m not a big fan of these exercises. I can see why materials writers like them, they seem fairly straightforward, but they tend to assume that all forms of that tense are the same (‘Let’s practise the Present Progressive!’) and don’t take account of grammatical metaphor like the one above. Also there is an implicit assumption that practicing these will lead to native-like acquisition of the form but, personally, I feel that the opposite is the case – that native-speaker competence allows the interpretation of the form.
Recently then I’ve been taking a different approach by giving the students the completed matching pair dialogues and discussing which are congruent and which are not. For those inconguent, we try to guess what the grammatical metaphor is (this is related to Speech Act theory in traditional sociolinguistics).