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