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