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