English verb conjugation
COULD OVERTURN

Regular verb: overturn - overturned - overturned

Affirmation

Simple form	V-ing form
I could overturn you could overturn he could overturn we could overturn you could overturn they could overturn	I could be overturning you could be overturning he could be overturning we could be overturning you could be overturning they could be overturning
Perfect	V-ing perfect
I could have overturned you could have overturned he could have overturned we could have overturned you could have overturned they could have overturned	I could have been overturning you could have been overturning he could have been overturning we could have been overturning you could have been overturning they could have been overturning

Negation

Simple form	V-ing form
I couldn't overturn you couldn't overturn he couldn't overturn we couldn't overturn you couldn't overturn they couldn't overturn	I couldn't be overturning you couldn't be overturning he couldn't be overturning we couldn't be overturning you couldn't be overturning they couldn't be overturning
Perfect	V-ing perfect
I couldn't have overturned you couldn't have overturned he couldn't have overturned we couldn't have overturned you couldn't have overturned they couldn't have overturned	I couldn't have been overturning you couldn't have been overturning he couldn't have been overturning we couldn't have been overturning you couldn't have been overturning they couldn't have been overturning

Interrogative form

Simple form	V-ing form
could I overturn? could you overturn? could he overturn? could we overturn? could you overturn? could they overturn?	could I be overturning? could you be overturning? could he be overturning? could we be overturning? could you be overturning? could they be overturning?
Perfect	V-ing perfect
could I have overturned? could you have overturned? could he have overturned? could we have overturned? could you have overturned? could they have overturned?	could I have been overturning? could you have been overturning? could he have been overturning? could we have been overturning? could you have been overturning? could they have been overturning?

Interro-negative form

Simple form	V-ing form
couldn't I overturn? couldn't you overturn? couldn't he overturn? couldn't we overturn? couldn't you overturn? couldn't they overturn?	couldn't I be overturning? couldn't you be overturning? couldn't he be overturning? couldn't we be overturning? couldn't you be overturning? couldn't they be overturning?
Perfect	V-ing perfect
couldn't I have overturned? couldn't you have overturned? couldn't he have overturned? couldn't we have overturned? couldn't you have overturned? couldn't they have overturned?	couldn't I have been overturning? couldn't you have been overturning? couldn't he have been overturning? couldn't we have been overturning? couldn't you have been overturning? couldn't they have been overturning?