I could suffice you could suffice he could suffice we could suffice you could suffice they could suffice
V-ing form
I could be sufficing you could be sufficing he could be sufficing we could be sufficing you could be sufficing they could be sufficing
Perfect
I could have sufficed you could have sufficed he could have sufficed we could have sufficed you could have sufficed they could have sufficed
V-ing perfect
I could have been sufficing you could have been sufficing he could have been sufficing we could have been sufficing you could have been sufficing they could have been sufficing
Negation
Simple form
I couldn't suffice you couldn't suffice he couldn't suffice we couldn't suffice you couldn't suffice they couldn't suffice
V-ing form
I couldn't be sufficing you couldn't be sufficing he couldn't be sufficing we couldn't be sufficing you couldn't be sufficing they couldn't be sufficing
Perfect
I couldn't have sufficed you couldn't have sufficed he couldn't have sufficed we couldn't have sufficed you couldn't have sufficed they couldn't have sufficed
V-ing perfect
I couldn't have been sufficing you couldn't have been sufficing he couldn't have been sufficing we couldn't have been sufficing you couldn't have been sufficing they couldn't have been sufficing
Interrogative form
Simple form
could I suffice? could you suffice? could he suffice? could we suffice? could you suffice? could they suffice?
V-ing form
could I be sufficing? could you be sufficing? could he be sufficing? could we be sufficing? could you be sufficing? could they be sufficing?
Perfect
could I have sufficed? could you have sufficed? could he have sufficed? could we have sufficed? could you have sufficed? could they have sufficed?
V-ing perfect
could I have been sufficing? could you have been sufficing? could he have been sufficing? could we have been sufficing? could you have been sufficing? could they have been sufficing?
Interro-negative form
Simple form
couldn't I suffice? couldn't you suffice? couldn't he suffice? couldn't we suffice? couldn't you suffice? couldn't they suffice?
V-ing form
couldn't I be sufficing? couldn't you be sufficing? couldn't he be sufficing? couldn't we be sufficing? couldn't you be sufficing? couldn't they be sufficing?
Perfect
couldn't I have sufficed? couldn't you have sufficed? couldn't he have sufficed? couldn't we have sufficed? couldn't you have sufficed? couldn't they have sufficed?
V-ing perfect
couldn't I have been sufficing? couldn't you have been sufficing? couldn't he have been sufficing? couldn't we have been sufficing? couldn't you have been sufficing? couldn't they have been sufficing?