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