to be likely to succeed.

The new drug holds promise for helping to control addiction.

• the oldest trick in the book
• the old guard
• the old school tie
• the only game in town
• the operative word
• the order of the day
• the other day
• the other side of the coin
• the other side of the tracks
• the pants off
• the pants off someone
• the parting of the ways
• the party is over
• the path of least resistance
• the patience of a saint
• the patience of Job
• the patter of tiny feet
• the pearly gates
• the pedal to the metal
• the pen is mightier than the sword.
• the penny drops
• the person in the street
• the pick of
• the pick of something
• the picture of