I could holster you could holster he could holster we could holster you could holster they could holster
V-ing form
I could be holstering you could be holstering he could be holstering we could be holstering you could be holstering they could be holstering
Perfect
I could have holstered you could have holstered he could have holstered we could have holstered you could have holstered they could have holstered
V-ing perfect
I could have been holstering you could have been holstering he could have been holstering we could have been holstering you could have been holstering they could have been holstering
Negation
Simple form
I couldn't holster you couldn't holster he couldn't holster we couldn't holster you couldn't holster they couldn't holster
V-ing form
I couldn't be holstering you couldn't be holstering he couldn't be holstering we couldn't be holstering you couldn't be holstering they couldn't be holstering
Perfect
I couldn't have holstered you couldn't have holstered he couldn't have holstered we couldn't have holstered you couldn't have holstered they couldn't have holstered
V-ing perfect
I couldn't have been holstering you couldn't have been holstering he couldn't have been holstering we couldn't have been holstering you couldn't have been holstering they couldn't have been holstering
Interrogative form
Simple form
could I holster? could you holster? could he holster? could we holster? could you holster? could they holster?
V-ing form
could I be holstering? could you be holstering? could he be holstering? could we be holstering? could you be holstering? could they be holstering?
Perfect
could I have holstered? could you have holstered? could he have holstered? could we have holstered? could you have holstered? could they have holstered?
V-ing perfect
could I have been holstering? could you have been holstering? could he have been holstering? could we have been holstering? could you have been holstering? could they have been holstering?
Interro-negative form
Simple form
couldn't I holster? couldn't you holster? couldn't he holster? couldn't we holster? couldn't you holster? couldn't they holster?
V-ing form
couldn't I be holstering? couldn't you be holstering? couldn't he be holstering? couldn't we be holstering? couldn't you be holstering? couldn't they be holstering?
Perfect
couldn't I have holstered? couldn't you have holstered? couldn't he have holstered? couldn't we have holstered? couldn't you have holstered? couldn't they have holstered?
V-ing perfect
couldn't I have been holstering? couldn't you have been holstering? couldn't he have been holstering? couldn't we have been holstering? couldn't you have been holstering? couldn't they have been holstering?