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