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