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 could not preacknowledge you could not preacknowledge he could not preacknowledge we could not preacknowledge you could not preacknowledge they could not preacknowledge
V-ing form
I could not be preacknowledging you could not be preacknowledging he could not be preacknowledging we could not be preacknowledging you could not be preacknowledging they could not be preacknowledging
Perfect
I could not have preacknowledged you could not have preacknowledged he could not have preacknowledged we could not have preacknowledged you could not have preacknowledged they could not have preacknowledged
V-ing perfect
I could not have been preacknowledging you could not have been preacknowledging he could not have been preacknowledging we could not have been preacknowledging you could not have been preacknowledging they could not 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
could I not preacknowledge? could you not preacknowledge? could he not preacknowledge? could we not preacknowledge? could you not preacknowledge? could they not preacknowledge?
V-ing form
could I not be preacknowledging? could you not be preacknowledging? could he not be preacknowledging? could we not be preacknowledging? could you not be preacknowledging? could they not be preacknowledging?
Perfect
could I not have preacknowledged? could you not have preacknowledged? could he not have preacknowledged? could we not have preacknowledged? could you not have preacknowledged? could they not have preacknowledged?
V-ing perfect
could I not have been preacknowledging? could you not have been preacknowledging? could he not have been preacknowledging? could we not have been preacknowledging? could you not have been preacknowledging? could they not have been preacknowledging?