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