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