I could mop you could mop she could mop we could mop you could mop they could mop
V-ing form
I could be mopping you could be mopping she could be mopping we could be mopping you could be mopping they could be mopping
Perfect
I could have mopped you could have mopped she could have mopped we could have mopped you could have mopped they could have mopped
V-ing perfect
I could have been mopping you could have been mopping she could have been mopping we could have been mopping you could have been mopping they could have been mopping
Negation
Simple form
I could not mop you could not mop she could not mop we could not mop you could not mop they could not mop
V-ing form
I could not be mopping you could not be mopping she could not be mopping we could not be mopping you could not be mopping they could not be mopping
Perfect
I could not have mopped you could not have mopped she could not have mopped we could not have mopped you could not have mopped they could not have mopped
V-ing perfect
I could not have been mopping you could not have been mopping she could not have been mopping we could not have been mopping you could not have been mopping they could not have been mopping
Interrogative form
Simple form
could I mop? could you mop? could she mop? could we mop? could you mop? could they mop?
V-ing form
could I be mopping? could you be mopping? could she be mopping? could we be mopping? could you be mopping? could they be mopping?
Perfect
could I have mopped? could you have mopped? could she have mopped? could we have mopped? could you have mopped? could they have mopped?
V-ing perfect
could I have been mopping? could you have been mopping? could she have been mopping? could we have been mopping? could you have been mopping? could they have been mopping?
Interro-negative form
Simple form
could I not mop? could you not mop? could she not mop? could we not mop? could you not mop? could they not mop?
V-ing form
could I not be mopping? could you not be mopping? could she not be mopping? could we not be mopping? could you not be mopping? could they not be mopping?
Perfect
could I not have mopped? could you not have mopped? could she not have mopped? could we not have mopped? could you not have mopped? could they not have mopped?
V-ing perfect
could I not have been mopping? could you not have been mopping? could she not have been mopping? could we not have been mopping? could you not have been mopping? could they not have been mopping?