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