English verb conjugation
COULD STUD

Regular verb: stud - studded - studded

Affirmation

Simple form	V-ing form
I could stud you could stud she could stud we could stud you could stud they could stud	I could be studding you could be studding she could be studding we could be studding you could be studding they could be studding
Perfect	V-ing perfect
I could have studded you could have studded she could have studded we could have studded you could have studded they could have studded	I could have been studding you could have been studding she could have been studding we could have been studding you could have been studding they could have been studding

Negation

Simple form	V-ing form
I couldn't stud you couldn't stud she couldn't stud we couldn't stud you couldn't stud they couldn't stud	I couldn't be studding you couldn't be studding she couldn't be studding we couldn't be studding you couldn't be studding they couldn't be studding
Perfect	V-ing perfect
I couldn't have studded you couldn't have studded she couldn't have studded we couldn't have studded you couldn't have studded they couldn't have studded	I couldn't have been studding you couldn't have been studding she couldn't have been studding we couldn't have been studding you couldn't have been studding they couldn't have been studding

Interrogative form

Simple form	V-ing form
could I stud? could you stud? could she stud? could we stud? could you stud? could they stud?	could I be studding? could you be studding? could she be studding? could we be studding? could you be studding? could they be studding?
Perfect	V-ing perfect
could I have studded? could you have studded? could she have studded? could we have studded? could you have studded? could they have studded?	could I have been studding? could you have been studding? could she have been studding? could we have been studding? could you have been studding? could they have been studding?

Interro-negative form

Simple form	V-ing form
couldn't I stud? couldn't you stud? couldn't she stud? couldn't we stud? couldn't you stud? couldn't they stud?	couldn't I be studding? couldn't you be studding? couldn't she be studding? couldn't we be studding? couldn't you be studding? couldn't they be studding?
Perfect	V-ing perfect
couldn't I have studded? couldn't you have studded? couldn't she have studded? couldn't we have studded? couldn't you have studded? couldn't they have studded?	couldn't I have been studding? couldn't you have been studding? couldn't she have been studding? couldn't we have been studding? couldn't you have been studding? couldn't they have been studding?