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