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