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 couldn't prewarn you couldn't prewarn he couldn't prewarn we couldn't prewarn you couldn't prewarn they couldn't prewarn	I couldn't be prewarning you couldn't be prewarning he couldn't be prewarning we couldn't be prewarning you couldn't be prewarning they couldn't be prewarning
Perfect	V-ing perfect
I couldn't have prewarned you couldn't have prewarned he couldn't have prewarned we couldn't have prewarned you couldn't have prewarned they couldn't have prewarned	I couldn't have been prewarning you couldn't have been prewarning he couldn't have been prewarning we couldn't have been prewarning you couldn't have been prewarning they couldn't 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
couldn't I prewarn? couldn't you prewarn? couldn't he prewarn? couldn't we prewarn? couldn't you prewarn? couldn't they prewarn?	couldn't I be prewarning? couldn't you be prewarning? couldn't he be prewarning? couldn't we be prewarning? couldn't you be prewarning? couldn't they be prewarning?
Perfect	V-ing perfect
couldn't I have prewarned? couldn't you have prewarned? couldn't he have prewarned? couldn't we have prewarned? couldn't you have prewarned? couldn't they have prewarned?	couldn't I have been prewarning? couldn't you have been prewarning? couldn't he have been prewarning? couldn't we have been prewarning? couldn't you have been prewarning? couldn't they have been prewarning?