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