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