I can duck you can duck she can duck we can duck you can duck they can duck
V-ing form
I can be ducking you can be ducking she can be ducking we can be ducking you can be ducking they can be ducking
Perfect
I can have ducked you can have ducked she can have ducked we can have ducked you can have ducked they can have ducked
V-ing perfect
I can have been ducking you can have been ducking she can have been ducking we can have been ducking you can have been ducking they can have been ducking
Negation
Simple form
I cannot duck you cannot duck she cannot duck we cannot duck you cannot duck they cannot duck
V-ing form
I cannot be ducking you cannot be ducking she cannot be ducking we cannot be ducking you cannot be ducking they cannot be ducking
Perfect
I cannot have ducked you cannot have ducked she cannot have ducked we cannot have ducked you cannot have ducked they cannot have ducked
V-ing perfect
I cannot have been ducking you cannot have been ducking she cannot have been ducking we cannot have been ducking you cannot have been ducking they cannot have been ducking
Interrogative form
Simple form
can I duck? can you duck? can she duck? can we duck? can you duck? can they duck?
V-ing form
can I be ducking? can you be ducking? can she be ducking? can we be ducking? can you be ducking? can they be ducking?
Perfect
can I have ducked? can you have ducked? can she have ducked? can we have ducked? can you have ducked? can they have ducked?
V-ing perfect
can I have been ducking? can you have been ducking? can she have been ducking? can we have been ducking? can you have been ducking? can they have been ducking?
Interro-negative form
Simple form
can I not duck? can you not duck? can she not duck? can we not duck? can you not duck? can they not duck?
V-ing form
can I not be ducking? can you not be ducking? can she not be ducking? can we not be ducking? can you not be ducking? can they not be ducking?
Perfect
can I not have ducked? can you not have ducked? can she not have ducked? can we not have ducked? can you not have ducked? can they not have ducked?
V-ing perfect
can I not have been ducking? can you not have been ducking? can she not have been ducking? can we not have been ducking? can you not have been ducking? can they not have been ducking?