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