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