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