Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I could decide decide you could decide decide he could decide decide we could decide decide you could decide decide they could decide decide
V-ing form
I could be decide deciding you could be decide deciding he could be decide deciding we could be decide deciding you could be decide deciding they could be decide deciding
Perfect
I could have decide decided you could have decide decided he could have decide decided we could have decide decided you could have decide decided they could have decide decided
V-ing perfect
I could have been decide deciding you could have been decide deciding he could have been decide deciding we could have been decide deciding you could have been decide deciding they could have been decide deciding
Negation
Simple form
I could not decide decide you could not decide decide he could not decide decide we could not decide decide you could not decide decide they could not decide decide
V-ing form
I could not be decide deciding you could not be decide deciding he could not be decide deciding we could not be decide deciding you could not be decide deciding they could not be decide deciding
Perfect
I could not have decide decided you could not have decide decided he could not have decide decided we could not have decide decided you could not have decide decided they could not have decide decided
V-ing perfect
I could not have been decide deciding you could not have been decide deciding he could not have been decide deciding we could not have been decide deciding you could not have been decide deciding they could not have been decide deciding
Interrogative form
Simple form
could I decide decide? could you decide decide? could he decide decide? could we decide decide? could you decide decide? could they decide decide?
V-ing form
could I be decide deciding? could you be decide deciding? could he be decide deciding? could we be decide deciding? could you be decide deciding? could they be decide deciding?
Perfect
could I have decide decided? could you have decide decided? could he have decide decided? could we have decide decided? could you have decide decided? could they have decide decided?
V-ing perfect
could I have been decide deciding? could you have been decide deciding? could he have been decide deciding? could we have been decide deciding? could you have been decide deciding? could they have been decide deciding?
Interro-negative form
Simple form
could I not decide decide? could you not decide decide? could he not decide decide? could we not decide decide? could you not decide decide? could they not decide decide?
V-ing form
could I not be decide deciding? could you not be decide deciding? could he not be decide deciding? could we not be decide deciding? could you not be decide deciding? could they not be decide deciding?
Perfect
could I not have decide decided? could you not have decide decided? could he not have decide decided? could we not have decide decided? could you not have decide decided? could they not have decide decided?
V-ing perfect
could I not have been decide deciding? could you not have been decide deciding? could he not have been decide deciding? could we not have been decide deciding? could you not have been decide deciding? could they not have been decide deciding?