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 could not frighten frighten you could not frighten frighten he could not frighten frighten we could not frighten frighten you could not frighten frighten they could not frighten frighten
V-ing form
I could not be frighten frightening you could not be frighten frightening he could not be frighten frightening we could not be frighten frightening you could not be frighten frightening they could not be frighten frightening
Perfect
I could not have frighten frightened you could not have frighten frightened he could not have frighten frightened we could not have frighten frightened you could not have frighten frightened they could not have frighten frightened
V-ing perfect
I could not have been frighten frightening you could not have been frighten frightening he could not have been frighten frightening we could not have been frighten frightening you could not have been frighten frightening they could not 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
could I not frighten frighten? could you not frighten frighten? could he not frighten frighten? could we not frighten frighten? could you not frighten frighten? could they not frighten frighten?
V-ing form
could I not be frighten frightening? could you not be frighten frightening? could he not be frighten frightening? could we not be frighten frightening? could you not be frighten frightening? could they not be frighten frightening?
Perfect
could I not have frighten frightened? could you not have frighten frightened? could he not have frighten frightened? could we not have frighten frightened? could you not have frighten frightened? could they not have frighten frightened?
V-ing perfect
could I not have been frighten frightening? could you not have been frighten frightening? could he not have been frighten frightening? could we not have been frighten frightening? could you not have been frighten frightening? could they not have been frighten frightening?