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