I could headquarter you could headquarter he could headquarter we could headquarter you could headquarter they could headquarter
V-ing form
I could be headquartering you could be headquartering he could be headquartering we could be headquartering you could be headquartering they could be headquartering
Perfect
I could have headquartered you could have headquartered he could have headquartered we could have headquartered you could have headquartered they could have headquartered
V-ing perfect
I could have been headquartering you could have been headquartering he could have been headquartering we could have been headquartering you could have been headquartering they could have been headquartering
Negation
Simple form
I could not headquarter you could not headquarter he could not headquarter we could not headquarter you could not headquarter they could not headquarter
V-ing form
I could not be headquartering you could not be headquartering he could not be headquartering we could not be headquartering you could not be headquartering they could not be headquartering
Perfect
I could not have headquartered you could not have headquartered he could not have headquartered we could not have headquartered you could not have headquartered they could not have headquartered
V-ing perfect
I could not have been headquartering you could not have been headquartering he could not have been headquartering we could not have been headquartering you could not have been headquartering they could not have been headquartering
Interrogative form
Simple form
could I headquarter? could you headquarter? could he headquarter? could we headquarter? could you headquarter? could they headquarter?
V-ing form
could I be headquartering? could you be headquartering? could he be headquartering? could we be headquartering? could you be headquartering? could they be headquartering?
Perfect
could I have headquartered? could you have headquartered? could he have headquartered? could we have headquartered? could you have headquartered? could they have headquartered?
V-ing perfect
could I have been headquartering? could you have been headquartering? could he have been headquartering? could we have been headquartering? could you have been headquartering? could they have been headquartering?
Interro-negative form
Simple form
could I not headquarter? could you not headquarter? could he not headquarter? could we not headquarter? could you not headquarter? could they not headquarter?
V-ing form
could I not be headquartering? could you not be headquartering? could he not be headquartering? could we not be headquartering? could you not be headquartering? could they not be headquartering?
Perfect
could I not have headquartered? could you not have headquartered? could he not have headquartered? could we not have headquartered? could you not have headquartered? could they not have headquartered?
V-ing perfect
could I not have been headquartering? could you not have been headquartering? could he not have been headquartering? could we not have been headquartering? could you not have been headquartering? could they not have been headquartering?