English verb conjugation
COULD CALL

Regular verb: call - called - called

Affirmation

Simple form	V-ing form
I could call you could call he could call we could call you could call they could call	I could be calling you could be calling he could be calling we could be calling you could be calling they could be calling
Perfect	V-ing perfect
I could have called you could have called he could have called we could have called you could have called they could have called	I could have been calling you could have been calling he could have been calling we could have been calling you could have been calling they could have been calling

Negation

Simple form	V-ing form
I couldn't call you couldn't call he couldn't call we couldn't call you couldn't call they couldn't call	I couldn't be calling you couldn't be calling he couldn't be calling we couldn't be calling you couldn't be calling they couldn't be calling
Perfect	V-ing perfect
I couldn't have called you couldn't have called he couldn't have called we couldn't have called you couldn't have called they couldn't have called	I couldn't have been calling you couldn't have been calling he couldn't have been calling we couldn't have been calling you couldn't have been calling they couldn't have been calling

Interrogative form

Simple form	V-ing form
could I call? could you call? could he call? could we call? could you call? could they call?	could I be calling? could you be calling? could he be calling? could we be calling? could you be calling? could they be calling?
Perfect	V-ing perfect
could I have called? could you have called? could he have called? could we have called? could you have called? could they have called?	could I have been calling? could you have been calling? could he have been calling? could we have been calling? could you have been calling? could they have been calling?

Interro-negative form

Simple form	V-ing form
couldn't I call? couldn't you call? couldn't he call? couldn't we call? couldn't you call? couldn't they call?	couldn't I be calling? couldn't you be calling? couldn't he be calling? couldn't we be calling? couldn't you be calling? couldn't they be calling?
Perfect	V-ing perfect
couldn't I have called? couldn't you have called? couldn't he have called? couldn't we have called? couldn't you have called? couldn't they have called?	couldn't I have been calling? couldn't you have been calling? couldn't he have been calling? couldn't we have been calling? couldn't you have been calling? couldn't they have been calling?