I could derive you could derive she could derive we could derive you could derive they could derive
V-ing form
I could be deriving you could be deriving she could be deriving we could be deriving you could be deriving they could be deriving
Perfect
I could have derived you could have derived she could have derived we could have derived you could have derived they could have derived
V-ing perfect
I could have been deriving you could have been deriving she could have been deriving we could have been deriving you could have been deriving they could have been deriving
Negation
Simple form
I could not derive you could not derive she could not derive we could not derive you could not derive they could not derive
V-ing form
I could not be deriving you could not be deriving she could not be deriving we could not be deriving you could not be deriving they could not be deriving
Perfect
I could not have derived you could not have derived she could not have derived we could not have derived you could not have derived they could not have derived
V-ing perfect
I could not have been deriving you could not have been deriving she could not have been deriving we could not have been deriving you could not have been deriving they could not have been deriving
Interrogative form
Simple form
could I derive? could you derive? could she derive? could we derive? could you derive? could they derive?
V-ing form
could I be deriving? could you be deriving? could she be deriving? could we be deriving? could you be deriving? could they be deriving?
Perfect
could I have derived? could you have derived? could she have derived? could we have derived? could you have derived? could they have derived?
V-ing perfect
could I have been deriving? could you have been deriving? could she have been deriving? could we have been deriving? could you have been deriving? could they have been deriving?
Interro-negative form
Simple form
could I not derive? could you not derive? could she not derive? could we not derive? could you not derive? could they not derive?
V-ing form
could I not be deriving? could you not be deriving? could she not be deriving? could we not be deriving? could you not be deriving? could they not be deriving?
Perfect
could I not have derived? could you not have derived? could she not have derived? could we not have derived? could you not have derived? could they not have derived?
V-ing perfect
could I not have been deriving? could you not have been deriving? could she not have been deriving? could we not have been deriving? could you not have been deriving? could they not have been deriving?