1. Sergio Estruch Miñana Esther García Castillo
Prepositions: at, on, in

2. Prepositions at, on, in, have several uses.
The most common applications are for time and places.

3. At (time) We use at before: For example:
Times: 6 o’clock, half past five, 4:45 pm.
Festival periods: Christmas, Easter.
Noon, midnight and night.
For example:
She was there at five o'clock.
We eat turkey at Christmas.
I watch TV at night.

4. On (time) We use on before: For example: Dates: March 1st…
Days: Tuesday, New Year’s Day, Valentine’s Day…
For example:
We will see you on Saturday.
My birthday is on March the 1st.

5. In (time) We use in before: For example: Months: February, June…
Seasons: winter, summer…
Years: 1998, 2003…
Times of the day: morning, afternoon, evening (not night).
For example:
Christmas is in December.
I go to the beach in summer.
I was born in 1994.
I study in the afternoon.

6. At (place) We use at to refer to a “general” location. For example:
He is at the bus stop.
He is at London now.

7. On (place)
We use on when we want to say that an object or person is on the surface of another object.
For example:
There is an orange on the table.
Don’t put your hands on my computer.

8. In (place)
We use in to specify that a noun (object, person etc) is inside.
For example:
Bogota is in Colombia.
My things are in my room.

10. Exercises http://www.learnenglishfeelgood.com/sp/prepositions1.html