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