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