Prepositions: In, On, and At

The prepositions in, on, and at can be used to indicate time and place. Notice how they are used in the following situations:

Preposition Time Place
In Year, Month, In 1999,
In December Country, State, City
In Japan, In Utah, InTaipei
On Day, Date On Saturday,
On May 1 Street On Main Street,
On 1st Ave.
At Time At 8:00,
At 7:30 Address
At 815 East Main Street.
In many languages, there is only one preposition for the above situations. In English there are three. Just remember that in usually indicates the "largest" time or place, and at usually indicates the "smallest" time or place. Examples: A: Where's your office? B: In Taipei, Taiwan. A: Really? What part of Taipei? B: It's on Chung Shan North Road. A: I know that area. Where exactly is it? B: It's at 105 Chung Shan North Road, next to the bookstore. C: When is the wedding? D: It's in June. C: What day? D: It's on Saturday, the 25th. C: What time? D: It starts at 6:00.