I could tag you could tag she could tag we could tag you could tag they could tag
V-ing form
I could be tagging you could be tagging she could be tagging we could be tagging you could be tagging they could be tagging
Perfect
I could have tagged you could have tagged she could have tagged we could have tagged you could have tagged they could have tagged
V-ing perfect
I could have been tagging you could have been tagging she could have been tagging we could have been tagging you could have been tagging they could have been tagging
Negation
Simple form
I could not tag you could not tag she could not tag we could not tag you could not tag they could not tag
V-ing form
I could not be tagging you could not be tagging she could not be tagging we could not be tagging you could not be tagging they could not be tagging
Perfect
I could not have tagged you could not have tagged she could not have tagged we could not have tagged you could not have tagged they could not have tagged
V-ing perfect
I could not have been tagging you could not have been tagging she could not have been tagging we could not have been tagging you could not have been tagging they could not have been tagging
Interrogative form
Simple form
could I tag? could you tag? could she tag? could we tag? could you tag? could they tag?
V-ing form
could I be tagging? could you be tagging? could she be tagging? could we be tagging? could you be tagging? could they be tagging?
Perfect
could I have tagged? could you have tagged? could she have tagged? could we have tagged? could you have tagged? could they have tagged?
V-ing perfect
could I have been tagging? could you have been tagging? could she have been tagging? could we have been tagging? could you have been tagging? could they have been tagging?
Interro-negative form
Simple form
could I not tag? could you not tag? could she not tag? could we not tag? could you not tag? could they not tag?
V-ing form
could I not be tagging? could you not be tagging? could she not be tagging? could we not be tagging? could you not be tagging? could they not be tagging?
Perfect
could I not have tagged? could you not have tagged? could she not have tagged? could we not have tagged? could you not have tagged? could they not have tagged?
V-ing perfect
could I not have been tagging? could you not have been tagging? could she not have been tagging? could we not have been tagging? could you not have been tagging? could they not have been tagging?