I could invalidate you could invalidate he could invalidate we could invalidate you could invalidate they could invalidate
V-ing form
I could be invalidating you could be invalidating he could be invalidating we could be invalidating you could be invalidating they could be invalidating
Perfect
I could have invalidated you could have invalidated he could have invalidated we could have invalidated you could have invalidated they could have invalidated
V-ing perfect
I could have been invalidating you could have been invalidating he could have been invalidating we could have been invalidating you could have been invalidating they could have been invalidating
Negation
Simple form
I could not invalidate you could not invalidate he could not invalidate we could not invalidate you could not invalidate they could not invalidate
V-ing form
I could not be invalidating you could not be invalidating he could not be invalidating we could not be invalidating you could not be invalidating they could not be invalidating
Perfect
I could not have invalidated you could not have invalidated he could not have invalidated we could not have invalidated you could not have invalidated they could not have invalidated
V-ing perfect
I could not have been invalidating you could not have been invalidating he could not have been invalidating we could not have been invalidating you could not have been invalidating they could not have been invalidating
Interrogative form
Simple form
could I invalidate? could you invalidate? could he invalidate? could we invalidate? could you invalidate? could they invalidate?
V-ing form
could I be invalidating? could you be invalidating? could he be invalidating? could we be invalidating? could you be invalidating? could they be invalidating?
Perfect
could I have invalidated? could you have invalidated? could he have invalidated? could we have invalidated? could you have invalidated? could they have invalidated?
V-ing perfect
could I have been invalidating? could you have been invalidating? could he have been invalidating? could we have been invalidating? could you have been invalidating? could they have been invalidating?
Interro-negative form
Simple form
could I not invalidate? could you not invalidate? could he not invalidate? could we not invalidate? could you not invalidate? could they not invalidate?
V-ing form
could I not be invalidating? could you not be invalidating? could he not be invalidating? could we not be invalidating? could you not be invalidating? could they not be invalidating?
Perfect
could I not have invalidated? could you not have invalidated? could he not have invalidated? could we not have invalidated? could you not have invalidated? could they not have invalidated?
V-ing perfect
could I not have been invalidating? could you not have been invalidating? could he not have been invalidating? could we not have been invalidating? could you not have been invalidating? could they not have been invalidating?