I could birl you could birl he could birl we could birl you could birl they could birl
Forme en V-ing
I could be birling you could be birling he could be birling we could be birling you could be birling they could be birling
Perfect
I could have birled you could have birled he could have birled we could have birled you could have birled they could have birled
Perfect en V-ing
I could have been birling you could have been birling he could have been birling we could have been birling you could have been birling they could have been birling
Négation
Forme simple
I could not birl you could not birl he could not birl we could not birl you could not birl they could not birl
Forme en V-ing
I could not be birling you could not be birling he could not be birling we could not be birling you could not be birling they could not be birling
Perfect
I could not have birled you could not have birled he could not have birled we could not have birled you could not have birled they could not have birled
Perfect en V-ing
I could not have been birling you could not have been birling he could not have been birling we could not have been birling you could not have been birling they could not have been birling
Forme interrogative
Forme simple
could I birl? could you birl? could he birl? could we birl? could you birl? could they birl?
Forme en V-ing
could I be birling? could you be birling? could he be birling? could we be birling? could you be birling? could they be birling?
Perfect
could I have birled? could you have birled? could he have birled? could we have birled? could you have birled? could they have birled?
Perfect en V-ing
could I have been birling? could you have been birling? could he have been birling? could we have been birling? could you have been birling? could they have been birling?
Forme interro-négative
Forme simple
could I not birl? could you not birl? could he not birl? could we not birl? could you not birl? could they not birl?
Forme en V-ing
could I not be birling? could you not be birling? could he not be birling? could we not be birling? could you not be birling? could they not be birling?
Perfect
could I not have birled? could you not have birled? could he not have birled? could we not have birled? could you not have birled? could they not have birled?
Perfect en V-ing
could I not have been birling? could you not have been birling? could he not have been birling? could we not have been birling? could you not have been birling? could they not have been birling?