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 cannot cough you cannot cough she cannot cough we cannot cough you cannot cough they cannot cough
V-ing form
I cannot be coughing you cannot be coughing she cannot be coughing we cannot be coughing you cannot be coughing they cannot be coughing
Perfect
I cannot have coughed you cannot have coughed she cannot have coughed we cannot have coughed you cannot have coughed they cannot have coughed
V-ing perfect
I cannot have been coughing you cannot have been coughing she cannot have been coughing we cannot have been coughing you cannot have been coughing they cannot 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 I not cough? can you not cough? can she not cough? can we not cough? can you not cough? can they not cough?
V-ing form
can I not be coughing? can you not be coughing? can she not be coughing? can we not be coughing? can you not be coughing? can they not be coughing?
Perfect
can I not have coughed? can you not have coughed? can she not have coughed? can we not have coughed? can you not have coughed? can they not have coughed?
V-ing perfect
can I not have been coughing? can you not have been coughing? can she not have been coughing? can we not have been coughing? can you not have been coughing? can they not have been coughing?