I could locate you could locate he could locate we could locate you could locate they could locate
V-ing form
I could be locating you could be locating he could be locating we could be locating you could be locating they could be locating
Perfect
I could have located you could have located he could have located we could have located you could have located they could have located
V-ing perfect
I could have been locating you could have been locating he could have been locating we could have been locating you could have been locating they could have been locating
Negation
Simple form
I could not locate you could not locate he could not locate we could not locate you could not locate they could not locate
V-ing form
I could not be locating you could not be locating he could not be locating we could not be locating you could not be locating they could not be locating
Perfect
I could not have located you could not have located he could not have located we could not have located you could not have located they could not have located
V-ing perfect
I could not have been locating you could not have been locating he could not have been locating we could not have been locating you could not have been locating they could not have been locating
Interrogative form
Simple form
could I locate? could you locate? could he locate? could we locate? could you locate? could they locate?
V-ing form
could I be locating? could you be locating? could he be locating? could we be locating? could you be locating? could they be locating?
Perfect
could I have located? could you have located? could he have located? could we have located? could you have located? could they have located?
V-ing perfect
could I have been locating? could you have been locating? could he have been locating? could we have been locating? could you have been locating? could they have been locating?
Interro-negative form
Simple form
could I not locate? could you not locate? could he not locate? could we not locate? could you not locate? could they not locate?
V-ing form
could I not be locating? could you not be locating? could he not be locating? could we not be locating? could you not be locating? could they not be locating?
Perfect
could I not have located? could you not have located? could he not have located? could we not have located? could you not have located? could they not have located?
V-ing perfect
could I not have been locating? could you not have been locating? could he not have been locating? could we not have been locating? could you not have been locating? could they not have been locating?