[little sage]

Hi,

I think it could be used to teach the Past Perfect Continuous, because there are some (weird) present results, and because the time the action stopped is so close to the present.

I can imagine, say, me washing the floors and my husband walking in. When he walks in, I stop washing the floor, I pause.

He could say:
1) What were you (just) doing? PC

2) What have you been doing? PPC

or, if the cloth is still in my hand and I'm obviously not done the action:

3) What are you doing? PrC

I think, though I'm no expert, all three would be correct but show slightly different perceptions about the situation: 1) the action is finished, had duration, was interrupted 2) gee, the room is clean now / why is she holding a dirty cloth? 3) the action is not finished

If your (very perceptive) students are really picky, then make a sign saying "Yesterday at 4:00" and have the acting students stand by that when they mime the actions. Then PC usage is more clear.

Hope this helps,
Karen