I can smoke you can smoke he can smoke we can smoke you can smoke they can smoke
V-ing form
I can be smoking you can be smoking he can be smoking we can be smoking you can be smoking they can be smoking
Perfect
I can have smoked you can have smoked he can have smoked we can have smoked you can have smoked they can have smoked
V-ing perfect
I can have been smoking you can have been smoking he can have been smoking we can have been smoking you can have been smoking they can have been smoking
Negation
Simple form
I can't smoke you can't smoke he can't smoke we can't smoke you can't smoke they can't smoke
V-ing form
I can't be smoking you can't be smoking he can't be smoking we can't be smoking you can't be smoking they can't be smoking
Perfect
I can't have smoked you can't have smoked he can't have smoked we can't have smoked you can't have smoked they can't have smoked
V-ing perfect
I can't have been smoking you can't have been smoking he can't have been smoking we can't have been smoking you can't have been smoking they can't have been smoking
Interrogative form
Simple form
can I smoke? can you smoke? can he smoke? can we smoke? can you smoke? can they smoke?
V-ing form
can I be smoking? can you be smoking? can he be smoking? can we be smoking? can you be smoking? can they be smoking?
Perfect
can I have smoked? can you have smoked? can he have smoked? can we have smoked? can you have smoked? can they have smoked?
V-ing perfect
can I have been smoking? can you have been smoking? can he have been smoking? can we have been smoking? can you have been smoking? can they have been smoking?
Interro-negative form
Simple form
can't I smoke? can't you smoke? can't he smoke? can't we smoke? can't you smoke? can't they smoke?
V-ing form
can't I be smoking? can't you be smoking? can't he be smoking? can't we be smoking? can't you be smoking? can't they be smoking?
Perfect
can't I have smoked? can't you have smoked? can't he have smoked? can't we have smoked? can't you have smoked? can't they have smoked?
V-ing perfect
can't I have been smoking? can't you have been smoking? can't he have been smoking? can't we have been smoking? can't you have been smoking? can't they have been smoking?