| on | in an irregular manner |
|---|---|
| on | not regularly |
| on | for examination (with an option to buy) |
| on | typically |
| on | (baseball) on first or second or third base |
| on | within range of a movie or television camera |
| on | performing or scheduled for duties |
| on | used with question words to convey surprise |
| on | with trust and confidence |
| on | lighted up by or as by fire or flame |
| on | vigilant |
| on | present and easily available |