English verb conjugation
COULD BUILD

Irregular verb: build - built - built

Affirmation

Simple form	V-ing form
I could build you could build he could build we could build you could build they could build	I could be building you could be building he could be building we could be building you could be building they could be building
Perfect	V-ing perfect
I could have built you could have built he could have built we could have built you could have built they could have built	I could have been building you could have been building he could have been building we could have been building you could have been building they could have been building

Negation

Simple form	V-ing form
I couldn't build you couldn't build he couldn't build we couldn't build you couldn't build they couldn't build	I couldn't be building you couldn't be building he couldn't be building we couldn't be building you couldn't be building they couldn't be building
Perfect	V-ing perfect
I couldn't have built you couldn't have built he couldn't have built we couldn't have built you couldn't have built they couldn't have built	I couldn't have been building you couldn't have been building he couldn't have been building we couldn't have been building you couldn't have been building they couldn't have been building

Interrogative form

Simple form	V-ing form
could I build? could you build? could he build? could we build? could you build? could they build?	could I be building? could you be building? could he be building? could we be building? could you be building? could they be building?
Perfect	V-ing perfect
could I have built? could you have built? could he have built? could we have built? could you have built? could they have built?	could I have been building? could you have been building? could he have been building? could we have been building? could you have been building? could they have been building?

Interro-negative form

Simple form	V-ing form
couldn't I build? couldn't you build? couldn't he build? couldn't we build? couldn't you build? couldn't they build?	couldn't I be building? couldn't you be building? couldn't he be building? couldn't we be building? couldn't you be building? couldn't they be building?
Perfect	V-ing perfect
couldn't I have built? couldn't you have built? couldn't he have built? couldn't we have built? couldn't you have built? couldn't they have built?	couldn't I have been building? couldn't you have been building? couldn't he have been building? couldn't we have been building? couldn't you have been building? couldn't they have been building?