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