English verb conjugation
COULD STAB

Regular verb: stab - stabbed - stabbed

Affirmation

Simple form	V-ing form
I could stab you could stab he could stab we could stab you could stab they could stab	I could be stabbing you could be stabbing he could be stabbing we could be stabbing you could be stabbing they could be stabbing
Perfect	V-ing perfect
I could have stabbed you could have stabbed he could have stabbed we could have stabbed you could have stabbed they could have stabbed	I could have been stabbing you could have been stabbing he could have been stabbing we could have been stabbing you could have been stabbing they could have been stabbing

Negation

Simple form	V-ing form
I couldn't stab you couldn't stab he couldn't stab we couldn't stab you couldn't stab they couldn't stab	I couldn't be stabbing you couldn't be stabbing he couldn't be stabbing we couldn't be stabbing you couldn't be stabbing they couldn't be stabbing
Perfect	V-ing perfect
I couldn't have stabbed you couldn't have stabbed he couldn't have stabbed we couldn't have stabbed you couldn't have stabbed they couldn't have stabbed	I couldn't have been stabbing you couldn't have been stabbing he couldn't have been stabbing we couldn't have been stabbing you couldn't have been stabbing they couldn't have been stabbing

Interrogative form

Simple form	V-ing form
could I stab? could you stab? could he stab? could we stab? could you stab? could they stab?	could I be stabbing? could you be stabbing? could he be stabbing? could we be stabbing? could you be stabbing? could they be stabbing?
Perfect	V-ing perfect
could I have stabbed? could you have stabbed? could he have stabbed? could we have stabbed? could you have stabbed? could they have stabbed?	could I have been stabbing? could you have been stabbing? could he have been stabbing? could we have been stabbing? could you have been stabbing? could they have been stabbing?

Interro-negative form

Simple form	V-ing form
couldn't I stab? couldn't you stab? couldn't he stab? couldn't we stab? couldn't you stab? couldn't they stab?	couldn't I be stabbing? couldn't you be stabbing? couldn't he be stabbing? couldn't we be stabbing? couldn't you be stabbing? couldn't they be stabbing?
Perfect	V-ing perfect
couldn't I have stabbed? couldn't you have stabbed? couldn't he have stabbed? couldn't we have stabbed? couldn't you have stabbed? couldn't they have stabbed?	couldn't I have been stabbing? couldn't you have been stabbing? couldn't he have been stabbing? couldn't we have been stabbing? couldn't you have been stabbing? couldn't they have been stabbing?