* Carry on.
* Turn on.
* Switch on.
* Press on.
* Count on.
* Rely on.
* Depend on.
* Focus on.
* Concentrate on.
* Dwell on.
* Reflect on.
* Meditate on.
* Base on.
* Ground on.
* Build on.
* Capitalize on.
* Cash in on.
* Pick up on.
* Catch on.
* Clue in on.
* Zero in on.
* Hone in on.
* Bear down on.
* Crack down on.
* Clamp down on.
* Back down on.
* Let down on.
* Bear up on.
* Cheer up on.
* Put down on.
* Set down on.
* Lay down on.
* Pull down on.
* Tear down on.
* Knock down on.
* Break down on.
* Fall down on.
* Get down on.
* Go down on.
* Move on.
* Get on.
* Go on.
* Put on.
* Take on.
* Hold on.
* Let on.
* Keep on.
* Carry on.
* Go (ahead) on.
* On the ball.
* On the beam.
* On the button.
* On the level.
* On the line.
* On the map.
* On the mend.
* On the move.
* On the nose.
* On the offensive.
* On the outside.
* On the pill.
* On the prowl.
* On the pull.
* On the QT.
* On the rebound.
* On the ropes.
* On the run.
* On the safe side.
* On the scent.
* On the skids.
* On the spot.
* On the spur of the moment.
* On the square.
* On the table.
* On the tip of one's tongue.
* On the town.
* On the verge.
* On the warpath.
* On the wing.