The prepositions in, on, and at can be used to indicate time and place.

Prepositions: In, On, and At (with specific times and places)

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 Decembe	Country, State, City In Japan, 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

n 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.

Prepositions with articles and locations

When talking about locations, use at to indicate the general vicinity or area, and in to
indicate inside the building, enclosed area, etc. For example:

at the swimming pool (on site)	in the swimming pool (in the pool itself i.e. in the water)
at the post office/bank (general)	in the post office/bank (inside the building)
at the zoo (visitors, general area)	in the zoo (animals in their cages)
at school	in the classroom

Sample sentences:

I met my wife at the theater. (while watching a movie) I spilled my drink in the theater (on the floor of the building) She works at the library on Wednesdays. She found a rare coin in the library (building). Dr. Jones works at the hospital every day. John was in the hospital for a week with a broken leg.

For school, prison, and mosque, the is used to indicate the building. No article indicates

the general situation. Note the following:

"practice"/situation	building
in school (studying, listening to teacher, etc.)	in the school (building)
in jail/prison (staying there as a criminal)	in the jail/prison (temporary)
in church (praying, listening to a sermon, etc.)	in the church (building)

Where's Mom?

in mosque (attending services)	in the mosque(fixing the windows)
at mosque	at the mosque

vocabulary around the house

the rooms in the house

Other Rooms

Attic	People store things in the attic.
Ballroom	A room in stately homes where rich people dance and concerts are held.
Box Room	A small room used for storage.
Cellar	Underneath the house.
Cloakroom	A small room where people put their coats.
Conservatory	A greenhouse attached to a house for the display of plants.
Dining Room	A room where people eat (see eating at home).
Drawing Room	A room in stately homes where rich people entertain.
Games Room	A room in large houses where games are played.
Hall	The entrance passage to a house.
Larder	A small room used for the storage of food.
Library	A room where books are kept.
Lounge	Another name for living room.
Music Room	A room where people play music.
Office	A room where people work.
Pantry	A small room used to store kitchen and dining items.
Parlour	Old fashioned word for living room.
Sitting Room	Another name for living room.
Spare Room/ Guest Room	A room where guests sleep.
Toilet	A room where people go to the toilet (often known as WC)
Utility Room	A room where appliances such as washing machines are used.