Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I could frighten frighten you could frighten frighten he could frighten frighten we could frighten frighten you could frighten frighten they could frighten frighten
V-ing form
I could be frighten frightening you could be frighten frightening he could be frighten frightening we could be frighten frightening you could be frighten frightening they could be frighten frightening
Perfect
I could have frighten frightened you could have frighten frightened he could have frighten frightened we could have frighten frightened you could have frighten frightened they could have frighten frightened
V-ing perfect
I could have been frighten frightening you could have been frighten frightening he could have been frighten frightening we could have been frighten frightening you could have been frighten frightening they could have been frighten frightening
Negation
Simple form
I couldn't frighten frighten you couldn't frighten frighten he couldn't frighten frighten we couldn't frighten frighten you couldn't frighten frighten they couldn't frighten frighten
V-ing form
I couldn't be frighten frightening you couldn't be frighten frightening he couldn't be frighten frightening we couldn't be frighten frightening you couldn't be frighten frightening they couldn't be frighten frightening
Perfect
I couldn't have frighten frightened you couldn't have frighten frightened he couldn't have frighten frightened we couldn't have frighten frightened you couldn't have frighten frightened they couldn't have frighten frightened
V-ing perfect
I couldn't have been frighten frightening you couldn't have been frighten frightening he couldn't have been frighten frightening we couldn't have been frighten frightening you couldn't have been frighten frightening they couldn't have been frighten frightening
Interrogative form
Simple form
could I frighten frighten? could you frighten frighten? could he frighten frighten? could we frighten frighten? could you frighten frighten? could they frighten frighten?
V-ing form
could I be frighten frightening? could you be frighten frightening? could he be frighten frightening? could we be frighten frightening? could you be frighten frightening? could they be frighten frightening?
Perfect
could I have frighten frightened? could you have frighten frightened? could he have frighten frightened? could we have frighten frightened? could you have frighten frightened? could they have frighten frightened?
V-ing perfect
could I have been frighten frightening? could you have been frighten frightening? could he have been frighten frightening? could we have been frighten frightening? could you have been frighten frightening? could they have been frighten frightening?
Interro-negative form
Simple form
couldn't I frighten frighten? couldn't you frighten frighten? couldn't he frighten frighten? couldn't we frighten frighten? couldn't you frighten frighten? couldn't they frighten frighten?
V-ing form
couldn't I be frighten frightening? couldn't you be frighten frightening? couldn't he be frighten frightening? couldn't we be frighten frightening? couldn't you be frighten frightening? couldn't they be frighten frightening?
Perfect
couldn't I have frighten frightened? couldn't you have frighten frightened? couldn't he have frighten frightened? couldn't we have frighten frightened? couldn't you have frighten frightened? couldn't they have frighten frightened?
V-ing perfect
couldn't I have been frighten frightening? couldn't you have been frighten frightening? couldn't he have been frighten frightening? couldn't we have been frighten frightening? couldn't you have been frighten frightening? couldn't they have been frighten frightening?