||not late, at the scheduled time
||Mary is always on time. She is very punctual.
|on top of
||informed, prepared, up on
||Addie stays on top of math by doing problems every day.
||in the right direction, on the rails
||After a few problems, our project is back on track.
||in court as a defendant, defending your actions
||The man charged with the assault is on trial now. He's in court.
||having a holiday from work or school
||I don't feel like getting up early when I'm on vacation.
|on your ass [B]
||wrong, misinformed, all wet
||He doesn't know how to manage a business. He's on his ass!
|on your deathbed
||very ill, nearly dead
||When I get a cold, you think I'm on my deathbed. Relax.
|on your guard
||Be on your guard when you buy a used car - don't buy a
|on your own
||independent, supporting yourself
||When you're on your own, you can stay out all night if you wish.
|on your side
||supporting you and your efforts
||"I'm on your side," Kelly said. "I want you to pass this course."