Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I could underlay sth you could underlay sth he could underlay sth we could underlay sth you could underlay sth they could underlay sth
V-ing form
I could be underlay sthing you could be underlay sthing he could be underlay sthing we could be underlay sthing you could be underlay sthing they could be underlay sthing
Perfect
I could have underlay sthed you could have underlay sthed he could have underlay sthed we could have underlay sthed you could have underlay sthed they could have underlay sthed
V-ing perfect
I could have been underlay sthing you could have been underlay sthing he could have been underlay sthing we could have been underlay sthing you could have been underlay sthing they could have been underlay sthing
Negation
Simple form
I could not underlay sth you could not underlay sth he could not underlay sth we could not underlay sth you could not underlay sth they could not underlay sth
V-ing form
I could not be underlay sthing you could not be underlay sthing he could not be underlay sthing we could not be underlay sthing you could not be underlay sthing they could not be underlay sthing
Perfect
I could not have underlay sthed you could not have underlay sthed he could not have underlay sthed we could not have underlay sthed you could not have underlay sthed they could not have underlay sthed
V-ing perfect
I could not have been underlay sthing you could not have been underlay sthing he could not have been underlay sthing we could not have been underlay sthing you could not have been underlay sthing they could not have been underlay sthing
Interrogative form
Simple form
could I underlay sth? could you underlay sth? could he underlay sth? could we underlay sth? could you underlay sth? could they underlay sth?
V-ing form
could I be underlay sthing? could you be underlay sthing? could he be underlay sthing? could we be underlay sthing? could you be underlay sthing? could they be underlay sthing?
Perfect
could I have underlay sthed? could you have underlay sthed? could he have underlay sthed? could we have underlay sthed? could you have underlay sthed? could they have underlay sthed?
V-ing perfect
could I have been underlay sthing? could you have been underlay sthing? could he have been underlay sthing? could we have been underlay sthing? could you have been underlay sthing? could they have been underlay sthing?
Interro-negative form
Simple form
could I not underlay sth? could you not underlay sth? could he not underlay sth? could we not underlay sth? could you not underlay sth? could they not underlay sth?
V-ing form
could I not be underlay sthing? could you not be underlay sthing? could he not be underlay sthing? could we not be underlay sthing? could you not be underlay sthing? could they not be underlay sthing?
Perfect
could I not have underlay sthed? could you not have underlay sthed? could he not have underlay sthed? could we not have underlay sthed? could you not have underlay sthed? could they not have underlay sthed?
V-ing perfect
could I not have been underlay sthing? could you not have been underlay sthing? could he not have been underlay sthing? could we not have been underlay sthing? could you not have been underlay sthing? could they not have been underlay sthing?