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