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I could have superseded you could have superseded he could have superseded we could have superseded you could have superseded they could have superseded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I couldn't have superseded you couldn't have superseded he couldn't have superseded we couldn't have superseded you couldn't have superseded they couldn't have superseded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could I have superseded? could you have superseded? could he have superseded? could we have superseded? could you have superseded? could they have superseded?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couldn't I have superseded? couldn't you have superseded?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