I can combat you can combat he can combat we can combat you can combat they can combat
V-ing form
I can be combating you can be combating he can be combating we can be combating you can be combating they can be combating
Perfect
I can have combated you can have combated he can have combated we can have combated you can have combated they can have combated
V-ing perfect
I can have been combating you can have been combating he can have been combating we can have been combating you can have been combating they can have been combating
Negation
Simple form
I can't combat you can't combat he can't combat we can't combat you can't combat they can't combat
V-ing form
I can't be combating you can't be combating he can't be combating we can't be combating you can't be combating they can't be combating
Perfect
I can't have combated you can't have combated he can't have combated we can't have combated you can't have combated they can't have combated
V-ing perfect
I can't have been combating you can't have been combating he can't have been combating we can't have been combating you can't have been combating they can't have been combating
Interrogative form
Simple form
can I combat? can you combat? can he combat? can we combat? can you combat? can they combat?
V-ing form
can I be combating? can you be combating? can he be combating? can we be combating? can you be combating? can they be combating?
Perfect
can I have combated? can you have combated? can he have combated? can we have combated? can you have combated? can they have combated?
V-ing perfect
can I have been combating? can you have been combating? can he have been combating? can we have been combating? can you have been combating? can they have been combating?
Interro-negative form
Simple form
can't I combat? can't you combat? can't he combat? can't we combat? can't you combat? can't they combat?
V-ing form
can't I be combating? can't you be combating? can't he be combating? can't we be combating? can't you be combating? can't they be combating?
Perfect
can't I have combated? can't you have combated? can't he have combated? can't we have combated? can't you have combated? can't they have combated?
V-ing perfect
can't I have been combating? can't you have been combating? can't he have been combating? can't we have been combating? can't you have been combating? can't they have been combating?