I could officiate you could officiate he could officiate we could officiate you could officiate they could officiate
V-ing form
I could be officiating you could be officiating he could be officiating we could be officiating you could be officiating they could be officiating
Perfect
I could have officiated you could have officiated he could have officiated we could have officiated you could have officiated they could have officiated
V-ing perfect
I could have been officiating you could have been officiating he could have been officiating we could have been officiating you could have been officiating they could have been officiating
Negation
Simple form
I could not officiate you could not officiate he could not officiate we could not officiate you could not officiate they could not officiate
V-ing form
I could not be officiating you could not be officiating he could not be officiating we could not be officiating you could not be officiating they could not be officiating
Perfect
I could not have officiated you could not have officiated he could not have officiated we could not have officiated you could not have officiated they could not have officiated
V-ing perfect
I could not have been officiating you could not have been officiating he could not have been officiating we could not have been officiating you could not have been officiating they could not have been officiating
Interrogative form
Simple form
could I officiate? could you officiate? could he officiate? could we officiate? could you officiate? could they officiate?
V-ing form
could I be officiating? could you be officiating? could he be officiating? could we be officiating? could you be officiating? could they be officiating?
Perfect
could I have officiated? could you have officiated? could he have officiated? could we have officiated? could you have officiated? could they have officiated?
V-ing perfect
could I have been officiating? could you have been officiating? could he have been officiating? could we have been officiating? could you have been officiating? could they have been officiating?
Interro-negative form
Simple form
could I not officiate? could you not officiate? could he not officiate? could we not officiate? could you not officiate? could they not officiate?
V-ing form
could I not be officiating? could you not be officiating? could he not be officiating? could we not be officiating? could you not be officiating? could they not be officiating?
Perfect
could I not have officiated? could you not have officiated? could he not have officiated? could we not have officiated? could you not have officiated? could they not have officiated?
V-ing perfect
could I not have been officiating? could you not have been officiating? could he not have been officiating? could we not have been officiating? could you not have been officiating? could they not have been officiating?