Privileges are given to prisoners if they behave well. ----- (PROVIDED). Prisoners __________________ they behave well.
Prisoners are given privileges provided (that) they behave well.
If the jury aren't convinced of his guilt, he won't go to prison.----- (UNLESS) He won't go to prison_________ that he's guilty.
He won't go to prison unless the jury are convinced that he's guilty.
I can't believe the only punishment he got was just a small fine.----- (OFF) I can't believe he __________ just a small fine.
I can't believe he was let off with/got off with just a small fine.