|on a roll
||having good luck, lucky streak
||I'm gonna play bingo all night. I'm lucky - I'm on a roll!
|on a silver platter
||like a beautiful gift, served in style
||Success won't come on a silver platter. You have to work for it.
|on a string
||controlled by a person, wrapped around his finger
||He's got you on a string, Bonny. Are you thinking for yourself?
||(See go on about)
|on all fours
||on your hands and knees, crawling around
||There was Julie, on all fours, looking for her contact lens.
|on an empty stomach
||without food in your stomach, on a full stomach
||He never has a drink on an empty stomach. He says it affects
||taking a purchase home to decide if you want it
||I buy clothes on approval so I can return them if they don't fit.
|on behalf of
||representing a group, acting for a group
||He presented the award to me on behalf of the community club.
||loaded on a vehicle, riding on a boat etc.
||Two thousand passengers were on board the ship to Canada.
|on cloud nine
||very happy, riding high
||When Bev received her diploma, she was on cloud nine.