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