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