Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I could disappear disappear you could disappear disappear he could disappear disappear we could disappear disappear you could disappear disappear they could disappear disappear
V-ing form
I could be disappear disappearing you could be disappear disappearing he could be disappear disappearing we could be disappear disappearing you could be disappear disappearing they could be disappear disappearing
Perfect
I could have disappear disappeared you could have disappear disappeared he could have disappear disappeared we could have disappear disappeared you could have disappear disappeared they could have disappear disappeared
V-ing perfect
I could have been disappear disappearing you could have been disappear disappearing he could have been disappear disappearing we could have been disappear disappearing you could have been disappear disappearing they could have been disappear disappearing
Negation
Simple form
I couldn't disappear disappear you couldn't disappear disappear he couldn't disappear disappear we couldn't disappear disappear you couldn't disappear disappear they couldn't disappear disappear
V-ing form
I couldn't be disappear disappearing you couldn't be disappear disappearing he couldn't be disappear disappearing we couldn't be disappear disappearing you couldn't be disappear disappearing they couldn't be disappear disappearing
Perfect
I couldn't have disappear disappeared you couldn't have disappear disappeared he couldn't have disappear disappeared we couldn't have disappear disappeared you couldn't have disappear disappeared they couldn't have disappear disappeared
V-ing perfect
I couldn't have been disappear disappearing you couldn't have been disappear disappearing he couldn't have been disappear disappearing we couldn't have been disappear disappearing you couldn't have been disappear disappearing they couldn't have been disappear disappearing
Interrogative form
Simple form
could I disappear disappear? could you disappear disappear? could he disappear disappear? could we disappear disappear? could you disappear disappear? could they disappear disappear?
V-ing form
could I be disappear disappearing? could you be disappear disappearing? could he be disappear disappearing? could we be disappear disappearing? could you be disappear disappearing? could they be disappear disappearing?
Perfect
could I have disappear disappeared? could you have disappear disappeared? could he have disappear disappeared? could we have disappear disappeared? could you have disappear disappeared? could they have disappear disappeared?
V-ing perfect
could I have been disappear disappearing? could you have been disappear disappearing? could he have been disappear disappearing? could we have been disappear disappearing? could you have been disappear disappearing? could they have been disappear disappearing?
Interro-negative form
Simple form
couldn't I disappear disappear? couldn't you disappear disappear? couldn't he disappear disappear? couldn't we disappear disappear? couldn't you disappear disappear? couldn't they disappear disappear?
V-ing form
couldn't I be disappear disappearing? couldn't you be disappear disappearing? couldn't he be disappear disappearing? couldn't we be disappear disappearing? couldn't you be disappear disappearing? couldn't they be disappear disappearing?
Perfect
couldn't I have disappear disappeared? couldn't you have disappear disappeared? couldn't he have disappear disappeared? couldn't we have disappear disappeared? couldn't you have disappear disappeared? couldn't they have disappear disappeared?
V-ing perfect
couldn't I have been disappear disappearing? couldn't you have been disappear disappearing? couldn't he have been disappear disappearing? couldn't we have been disappear disappearing? couldn't you have been disappear disappearing? couldn't they have been disappear disappearing?