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