I can cough you can cough she can cough we can cough you can cough they can cough
V-ing form
I can be coughing you can be coughing she can be coughing we can be coughing you can be coughing they can be coughing
Perfect
I can have coughed you can have coughed she can have coughed we can have coughed you can have coughed they can have coughed
V-ing perfect
I can have been coughing you can have been coughing she can have been coughing we can have been coughing you can have been coughing they can have been coughing
Negation
Simple form
I can't cough you can't cough she can't cough we can't cough you can't cough they can't cough
V-ing form
I can't be coughing you can't be coughing she can't be coughing we can't be coughing you can't be coughing they can't be coughing
Perfect
I can't have coughed you can't have coughed she can't have coughed we can't have coughed you can't have coughed they can't have coughed
V-ing perfect
I can't have been coughing you can't have been coughing she can't have been coughing we can't have been coughing you can't have been coughing they can't have been coughing
Interrogative form
Simple form
can I cough? can you cough? can she cough? can we cough? can you cough? can they cough?
V-ing form
can I be coughing? can you be coughing? can she be coughing? can we be coughing? can you be coughing? can they be coughing?
Perfect
can I have coughed? can you have coughed? can she have coughed? can we have coughed? can you have coughed? can they have coughed?
V-ing perfect
can I have been coughing? can you have been coughing? can she have been coughing? can we have been coughing? can you have been coughing? can they have been coughing?
Interro-negative form
Simple form
can't I cough? can't you cough? can't she cough? can't we cough? can't you cough? can't they cough?
V-ing form
can't I be coughing? can't you be coughing? can't she be coughing? can't we be coughing? can't you be coughing? can't they be coughing?
Perfect
can't I have coughed? can't you have coughed? can't she have coughed? can't we have coughed? can't you have coughed? can't they have coughed?
V-ing perfect
can't I have been coughing? can't you have been coughing? can't she have been coughing? can't we have been coughing? can't you have been coughing? can't they have been coughing?