In English, there are several types of prepositions, including simple, complex, double, and compound-complex prepositions. Simple prepositions, such as “in”, “on”, “at”, are used independently. Complex prepositions consist of multiple words, such as “next to”. Double prepositions, which include a combination of a simple preposition and an adverb, for example “up in”, are used to express complex relationships. Compound-complex prepositions, which have a combination of a simple preposition, a preposition, and an adverb, for example “in front of”, expand the range of possible usage options.

Prepositions: at, in, on

AT

• Use “at” for specific times:
  • “I will meet you at 3 pm.”
  • “The show starts at noon.”
• Use “at” for addresses and locations referring to a point:
  • “He lives at 24 Oak Street.”
  • “Let’s meet at the corner of Main St and 1st Ave.”
• Use “at” for events or temporary activities happening at locations:
  • “There was a concert at the park.”
  • “I saw a play at the theater.”

IN

• Use “in” for periods of time without specifying an exact point:
  • “I was born in 1992.” (year)
  • “She’ll visit in July.” (month)
  • “It happened in the morning.” (part of day)
• Use “in” for enclosed spaces:
  • “He’s in the kitchen.”
  • “The cat is in the box.”
• Use “in” for locations perceived as enclosed areas:
  • “They live in Seattle.” (city)
  • “We’re stuck in traffic.”

ON

• Use “on” for surfaces:
  • “Put the book on the table.”
  • “There’s a stain on the carpet.”
• Use “on” for days and dates:
  • “Let’s meet on Monday.”
  • “Her birthday is on May 15th.”
• Use “on” for streets, representing a linear surface:
  • “The shop is on Main Street.”
  • “We’re driving on the highway.”
• Use “on” for modes of transportation:
  • “She arrived on the train.”
  • “We’re going on a cruise.”

The main difference is that “at” is used for exact time/place, “in” for time periods and enclosed areas, and “on” for surfaces, days/dates, and modes of transportation.