English verb conjugation
COULD STUDY

Regular verb: study - studied - studied

Affirmation

Simple form	V-ing form
I could study you could study he could study we could study you could study they could study	I could be studying you could be studying he could be studying we could be studying you could be studying they could be studying
Perfect	V-ing perfect
I could have studied you could have studied he could have studied we could have studied you could have studied they could have studied	I could have been studying you could have been studying he could have been studying we could have been studying you could have been studying they could have been studying

Negation

Simple form	V-ing form
I couldn't study you couldn't study he couldn't study we couldn't study you couldn't study they couldn't study	I couldn't be studying you couldn't be studying he couldn't be studying we couldn't be studying you couldn't be studying they couldn't be studying
Perfect	V-ing perfect
I couldn't have studied you couldn't have studied he couldn't have studied we couldn't have studied you couldn't have studied they couldn't have studied	I couldn't have been studying you couldn't have been studying he couldn't have been studying we couldn't have been studying you couldn't have been studying they couldn't have been studying

Interrogative form

Simple form	V-ing form
could I study? could you study? could he study? could we study? could you study? could they study?	could I be studying? could you be studying? could he be studying? could we be studying? could you be studying? could they be studying?
Perfect	V-ing perfect
could I have studied? could you have studied? could he have studied? could we have studied? could you have studied? could they have studied?	could I have been studying? could you have been studying? could he have been studying? could we have been studying? could you have been studying? could they have been studying?

Interro-negative form

Simple form	V-ing form
couldn't I study? couldn't you study? couldn't he study? couldn't we study? couldn't you study? couldn't they study?	couldn't I be studying? couldn't you be studying? couldn't he be studying? couldn't we be studying? couldn't you be studying? couldn't they be studying?
Perfect	V-ing perfect
couldn't I have studied? couldn't you have studied? couldn't he have studied? couldn't we have studied? couldn't you have studied? couldn't they have studied?	couldn't I have been studying? couldn't you have been studying? couldn't he have been studying? couldn't we have been studying? couldn't you have been studying? couldn't they have been studying?