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