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