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