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