spokenused to say who is going to pay for something:
The drinks are on me!
Each table will get a bottle of champagneon the house (=paid for by the restaurant, hotel etc).
used to say what number you should use in order to telephone someone [= at American English]
You can contact me on this number.
causing somebody problems
used when something bad happens to you, for example when something you are using suddenly stops working, or someone you have a relationship with suddenly leaves you:
Suddenly the telephone went dead on me.
Dorothy's first husband walked out on her.
WORD CHOICE WORD CHOICE at, in, onTalking about timeUse atwith clock times• at one o'clock • at 6.30with points of time in the day• at midnight • at noon • at dawn • at sunsetwith holiday periods, meaning the few days around the holiday• at Easter • at Diwaliwith weekend, in British English• See you at the weekend! • At weekends we go out.Use inwith parts of the day• in the morning• in the evening• I never watch TV in the daytime.with months, seasons, years, centuries• in May • in summertime • in 2004• in the 21st centuryUse onwith dates and specific days• on 29th July • on Tuesday afternoons• on the last day of termwith weekend, in American English• We sometimes go there on weekends.Talking about position and placeUse atwith particular positions or places• at the end of the corridor • at the back of the room • at the corner of the street to mean 'next to' or 'beside'• She sat at her desk. • He stopped me at the door.with words for buildings, for example airport, university, restaurant, art gallery• at the airport • at the Lyceum theatrewith city or place names, when you are talking about stopping during a journey• Does this train stop at Watford?!! BUT otherwise use in - see belowUse inwith a position or place, when something or someone is inside a larger thing such as a room• in the bath • in the kitchen • in the garden • in the doorwaywith cities, counties, states, and countries• When will you arrive in Tokyo?• He lives in Germany. • She's working in California.with the names of squares, plazas etc• in Times SquareUse onwith a position or place, when one thing is attached to or touching another• a spot on the end of her nose• a jacket on the back of a chairwith street names• on the High Street • on 42nd Street • on Broadway ➔ See alsoat
Definition from the Longman Dictionary of Contemporary English Advanced Learner's Dictionary.