Prepositions are used to locate something in time and space, modify a noun; or tell when or where or under what conditions something happened. The following are guidelines for using prepositions correctly. This covers many common situations.
Prepositions of Time: at, in, on
|at is for specific times
|The exam is at 12:15 PM
|in is for nonspecific times during a day/month/year.
|The exam is in the morning
|on for days and dates
|The exam is on Monday.
The exam is on Christmas Day.
Prepositions of Place: at, in, on
|We use at for specific addresses.
|I live at 50 Pong Lai Road.
|We use in for the names of land-areas (towns, counties, states, countries, and continents).
|I live in Taipei.
|We use on for the names of streets, avenues, etc.
|I live on Pong Lai Road.
Prepositions for describing our work:
|I work at Comtrend
|in the marketing department, as a technical writer.
|I am working on a new manual