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