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