[susan53]

Quote emile

Teacher - ...so we use Present Simple for something generally true, and Present Continuous for a current action.

Student - Yes, I am understanding.

--------------

I would argue that there are far fewer exceptions than most teachers think - just bad rules. Take this one. The whole point is that we don't use the Continuous for a current action - we use it for a temporary action - ie one which has started before the point of reference, continues after it but has a foreseeable end. So eg I'm writing this reply. I started a minute ago, the reference point is now and we all know that in a few hours I'll no longer be here. Similarly : I was waiting for the bus when the accident happened. At the moment of the accident (the reference point) I had already started waiting for the bus, and it's clear that the action finished shortly afterwards when the bus arrived. Whether it's present, past, future or anything else is immaterial - that's expressed by the tense of the BE auxiliary and may change. But the meaning of continuous aspect remains the same.

The point about I understand is that it's not a temporary action - there's no foreseeable end to it. If you understand you understand permanently- And permanent actions are expressed with simple aspect. That doesn't mean of course that things can't change - any permanent action, whether I live in Milan, water boils at 100°, or I understand could change under certain circumstances. But the actual occurrence of those circumstances is not foreseeable at the time of speaking.

This is just an example. But time after time that teachers say "That's an exception" it really means that they've not worked out the correct formulation of the rule. Little wonder then that students aren't understanding ...