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