English verb conjugation
COULD PREWARN

Regular verb: prewarn - prewarned - prewarned

Affirmation

Simple form	V-ing form
I could prewarn you could prewarn he could prewarn we could prewarn you could prewarn they could prewarn	I could be prewarning you could be prewarning he could be prewarning we could be prewarning you could be prewarning they could be prewarning
Perfect	V-ing perfect
I could have prewarned you could have prewarned he could have prewarned we could have prewarned you could have prewarned they could have prewarned	I could have been prewarning you could have been prewarning he could have been prewarning we could have been prewarning you could have been prewarning they could have been prewarning

Negation

Simple form	V-ing form
I could not prewarn you could not prewarn he could not prewarn we could not prewarn you could not prewarn they could not prewarn	I could not be prewarning you could not be prewarning he could not be prewarning we could not be prewarning you could not be prewarning they could not be prewarning
Perfect	V-ing perfect
I could not have prewarned you could not have prewarned he could not have prewarned we could not have prewarned you could not have prewarned they could not have prewarned	I could not have been prewarning you could not have been prewarning he could not have been prewarning we could not have been prewarning you could not have been prewarning they could not have been prewarning

Interrogative form

Simple form	V-ing form
could I prewarn? could you prewarn? could he prewarn? could we prewarn? could you prewarn? could they prewarn?	could I be prewarning? could you be prewarning? could he be prewarning? could we be prewarning? could you be prewarning? could they be prewarning?
Perfect	V-ing perfect
could I have prewarned? could you have prewarned? could he have prewarned? could we have prewarned? could you have prewarned? could they have prewarned?	could I have been prewarning? could you have been prewarning? could he have been prewarning? could we have been prewarning? could you have been prewarning? could they have been prewarning?

Interro-negative form

Simple form	V-ing form
could I not prewarn? could you not prewarn? could he not prewarn? could we not prewarn? could you not prewarn? could they not prewarn?	could I not be prewarning? could you not be prewarning? could he not be prewarning? could we not be prewarning? could you not be prewarning? could they not be prewarning?
Perfect	V-ing perfect
could I not have prewarned? could you not have prewarned? could he not have prewarned? could we not have prewarned? could you not have prewarned? could they not have prewarned?	could I not have been prewarning? could you not have been prewarning? could he not have been prewarning? could we not have been prewarning? could you not have been prewarning? could they not have been prewarning?