English verb conjugation
COULD PERTURB

Regular verb: perturb - perturbed - perturbed

Affirmation

Simple form	V-ing form
I could perturb you could perturb he could perturb we could perturb you could perturb they could perturb	I could be perturbing you could be perturbing he could be perturbing we could be perturbing you could be perturbing they could be perturbing
Perfect	V-ing perfect
I could have perturbed you could have perturbed he could have perturbed we could have perturbed you could have perturbed they could have perturbed	I could have been perturbing you could have been perturbing he could have been perturbing we could have been perturbing you could have been perturbing they could have been perturbing

Negation

Simple form	V-ing form
I couldn't perturb you couldn't perturb he couldn't perturb we couldn't perturb you couldn't perturb they couldn't perturb	I couldn't be perturbing you couldn't be perturbing he couldn't be perturbing we couldn't be perturbing you couldn't be perturbing they couldn't be perturbing
Perfect	V-ing perfect
I couldn't have perturbed you couldn't have perturbed he couldn't have perturbed we couldn't have perturbed you couldn't have perturbed they couldn't have perturbed	I couldn't have been perturbing you couldn't have been perturbing he couldn't have been perturbing we couldn't have been perturbing you couldn't have been perturbing they couldn't have been perturbing

Interrogative form

Simple form	V-ing form
could I perturb? could you perturb? could he perturb? could we perturb? could you perturb? could they perturb?	could I be perturbing? could you be perturbing? could he be perturbing? could we be perturbing? could you be perturbing? could they be perturbing?
Perfect	V-ing perfect
could I have perturbed? could you have perturbed? could he have perturbed? could we have perturbed? could you have perturbed? could they have perturbed?	could I have been perturbing? could you have been perturbing? could he have been perturbing? could we have been perturbing? could you have been perturbing? could they have been perturbing?

Interro-negative form

Simple form	V-ing form
couldn't I perturb? couldn't you perturb? couldn't he perturb? couldn't we perturb? couldn't you perturb? couldn't they perturb?	couldn't I be perturbing? couldn't you be perturbing? couldn't he be perturbing? couldn't we be perturbing? couldn't you be perturbing? couldn't they be perturbing?
Perfect	V-ing perfect
couldn't I have perturbed? couldn't you have perturbed? couldn't he have perturbed? couldn't we have perturbed? couldn't you have perturbed? couldn't they have perturbed?	couldn't I have been perturbing? couldn't you have been perturbing? couldn't he have been perturbing? couldn't we have been perturbing? couldn't you have been perturbing? couldn't they have been perturbing?