I could swell you could swell she could swell we could swell you could swell they could swell
V-ing form
I could be swelling you could be swelling she could be swelling we could be swelling you could be swelling they could be swelling
Perfect
I could have swelled, swollen you could have swelled, swollen she could have swelled, swollen we could have swelled, swollen you could have swelled, swollen they could have swelled, swollen
V-ing perfect
I could have been swelling you could have been swelling she could have been swelling we could have been swelling you could have been swelling they could have been swelling
Negation
Simple form
I couldn't swell you couldn't swell she couldn't swell we couldn't swell you couldn't swell they couldn't swell
V-ing form
I couldn't be swelling you couldn't be swelling she couldn't be swelling we couldn't be swelling you couldn't be swelling they couldn't be swelling
Perfect
I couldn't have swelled, swollen you couldn't have swelled, swollen she couldn't have swelled, swollen we couldn't have swelled, swollen you couldn't have swelled, swollen they couldn't have swelled, swollen
V-ing perfect
I couldn't have been swelling you couldn't have been swelling she couldn't have been swelling we couldn't have been swelling you couldn't have been swelling they couldn't have been swelling
Interrogative form
Simple form
could I swell? could you swell? could she swell? could we swell? could you swell? could they swell?
V-ing form
could I be swelling? could you be swelling? could she be swelling? could we be swelling? could you be swelling? could they be swelling?
Perfect
could I have swelled, swollen? could you have swelled, swollen? could she have swelled, swollen? could we have swelled, swollen? could you have swelled, swollen? could they have swelled, swollen?
V-ing perfect
could I have been swelling? could you have been swelling? could she have been swelling? could we have been swelling? could you have been swelling? could they have been swelling?
Interro-negative form
Simple form
couldn't I swell? couldn't you swell? couldn't she swell? couldn't we swell? couldn't you swell? couldn't they swell?
V-ing form
couldn't I be swelling? couldn't you be swelling? couldn't she be swelling? couldn't we be swelling? couldn't you be swelling? couldn't they be swelling?
Perfect
couldn't I have swelled, swollen? couldn't you have swelled, swollen? couldn't she have swelled, swollen? couldn't we have swelled, swollen? couldn't you have swelled, swollen? couldn't they have swelled, swollen?
V-ing perfect
couldn't I have been swelling? couldn't you have been swelling? couldn't she have been swelling? couldn't we have been swelling? couldn't you have been swelling? couldn't they have been swelling?