Oxford Dictionary says: "while–at the same time as sth else is happening
eg: You can go swimming while I’m having lunch."
so I am confused. Why doesn’t Daddy Pig say "You go and dry yourselves while I’m polishing the car."?
Your question asks about the following forms:
- You do this while I do that.
- You do this while I’m doing that.
It’s arguable that the continuous form can apply to the situation where “that” is currently being performed whereas the base form can’t carry that sense. But both sentences can also idiomatically convey the same sense – an apportionment of roles where both “this” and “that” are only contemplated (not being performed) when the sentence is spoke.
The core difference is that the base form references the tasks in their entirety whereas the continuous form references the period/duration that “that” is being performed. Despite this notional difference, the use of “while” makes the pragmatics of the two sentences identical when “that” is not being performed at the time of utterance.