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