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