I could evolve you could evolve she could evolve we could evolve you could evolve they could evolve
V-ing form
I could be evolving you could be evolving she could be evolving we could be evolving you could be evolving they could be evolving
Perfect
I could have evolved you could have evolved she could have evolved we could have evolved you could have evolved they could have evolved
V-ing perfect
I could have been evolving you could have been evolving she could have been evolving we could have been evolving you could have been evolving they could have been evolving
Negation
Simple form
I couldn't evolve you couldn't evolve she couldn't evolve we couldn't evolve you couldn't evolve they couldn't evolve
V-ing form
I couldn't be evolving you couldn't be evolving she couldn't be evolving we couldn't be evolving you couldn't be evolving they couldn't be evolving
Perfect
I couldn't have evolved you couldn't have evolved she couldn't have evolved we couldn't have evolved you couldn't have evolved they couldn't have evolved
V-ing perfect
I couldn't have been evolving you couldn't have been evolving she couldn't have been evolving we couldn't have been evolving you couldn't have been evolving they couldn't have been evolving
Interrogative form
Simple form
could I evolve? could you evolve? could she evolve? could we evolve? could you evolve? could they evolve?
V-ing form
could I be evolving? could you be evolving? could she be evolving? could we be evolving? could you be evolving? could they be evolving?
Perfect
could I have evolved? could you have evolved? could she have evolved? could we have evolved? could you have evolved? could they have evolved?
V-ing perfect
could I have been evolving? could you have been evolving? could she have been evolving? could we have been evolving? could you have been evolving? could they have been evolving?
Interro-negative form
Simple form
couldn't I evolve? couldn't you evolve? couldn't she evolve? couldn't we evolve? couldn't you evolve? couldn't they evolve?
V-ing form
couldn't I be evolving? couldn't you be evolving? couldn't she be evolving? couldn't we be evolving? couldn't you be evolving? couldn't they be evolving?
Perfect
couldn't I have evolved? couldn't you have evolved? couldn't she have evolved? couldn't we have evolved? couldn't you have evolved? couldn't they have evolved?
V-ing perfect
couldn't I have been evolving? couldn't you have been evolving? couldn't she have been evolving? couldn't we have been evolving? couldn't you have been evolving? couldn't they have been evolving?