I could ache you could ache she could ache we could ache you could ache they could ache
V-ing form
I could be aching you could be aching she could be aching we could be aching you could be aching they could be aching
Perfect
I could have ached you could have ached she could have ached we could have ached you could have ached they could have ached
V-ing perfect
I could have been aching you could have been aching she could have been aching we could have been aching you could have been aching they could have been aching
Negation
Simple form
I couldn't ache you couldn't ache she couldn't ache we couldn't ache you couldn't ache they couldn't ache
V-ing form
I couldn't be aching you couldn't be aching she couldn't be aching we couldn't be aching you couldn't be aching they couldn't be aching
Perfect
I couldn't have ached you couldn't have ached she couldn't have ached we couldn't have ached you couldn't have ached they couldn't have ached
V-ing perfect
I couldn't have been aching you couldn't have been aching she couldn't have been aching we couldn't have been aching you couldn't have been aching they couldn't have been aching
Interrogative form
Simple form
could I ache? could you ache? could she ache? could we ache? could you ache? could they ache?
V-ing form
could I be aching? could you be aching? could she be aching? could we be aching? could you be aching? could they be aching?
Perfect
could I have ached? could you have ached? could she have ached? could we have ached? could you have ached? could they have ached?
V-ing perfect
could I have been aching? could you have been aching? could she have been aching? could we have been aching? could you have been aching? could they have been aching?
Interro-negative form
Simple form
couldn't I ache? couldn't you ache? couldn't she ache? couldn't we ache? couldn't you ache? couldn't they ache?
V-ing form
couldn't I be aching? couldn't you be aching? couldn't she be aching? couldn't we be aching? couldn't you be aching? couldn't they be aching?
Perfect
couldn't I have ached? couldn't you have ached? couldn't she have ached? couldn't we have ached? couldn't you have ached? couldn't they have ached?
V-ing perfect
couldn't I have been aching? couldn't you have been aching? couldn't she have been aching? couldn't we have been aching? couldn't you have been aching? couldn't they have been aching?