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