I can sigh you can sigh he can sigh we can sigh you can sigh they can sigh
V-ing form
I can be sighing you can be sighing he can be sighing we can be sighing you can be sighing they can be sighing
Perfect
I can have sighed you can have sighed he can have sighed we can have sighed you can have sighed they can have sighed
V-ing perfect
I can have been sighing you can have been sighing he can have been sighing we can have been sighing you can have been sighing they can have been sighing
Negation
Simple form
I can't sigh you can't sigh he can't sigh we can't sigh you can't sigh they can't sigh
V-ing form
I can't be sighing you can't be sighing he can't be sighing we can't be sighing you can't be sighing they can't be sighing
Perfect
I can't have sighed you can't have sighed he can't have sighed we can't have sighed you can't have sighed they can't have sighed
V-ing perfect
I can't have been sighing you can't have been sighing he can't have been sighing we can't have been sighing you can't have been sighing they can't have been sighing
Interrogative form
Simple form
can I sigh? can you sigh? can he sigh? can we sigh? can you sigh? can they sigh?
V-ing form
can I be sighing? can you be sighing? can he be sighing? can we be sighing? can you be sighing? can they be sighing?
Perfect
can I have sighed? can you have sighed? can he have sighed? can we have sighed? can you have sighed? can they have sighed?
V-ing perfect
can I have been sighing? can you have been sighing? can he have been sighing? can we have been sighing? can you have been sighing? can they have been sighing?
Interro-negative form
Simple form
can't I sigh? can't you sigh? can't he sigh? can't we sigh? can't you sigh? can't they sigh?
V-ing form
can't I be sighing? can't you be sighing? can't he be sighing? can't we be sighing? can't you be sighing? can't they be sighing?
Perfect
can't I have sighed? can't you have sighed? can't he have sighed? can't we have sighed? can't you have sighed? can't they have sighed?
V-ing perfect
can't I have been sighing? can't you have been sighing? can't he have been sighing? can't we have been sighing? can't you have been sighing? can't they have been sighing?