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