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