Prepositions of Time

A preposition links (una preposición une) nouns, pronouns and phrases to other words in a sentence. The word or phrase that the preposition introduces is called the object of the preposition.

A preposition usually indicates the temporal, spatial or logical relationship (relación lógica o con el espacio) of its object (de su objeto) to the rest of the sentence (con el resto de la oración) as in the following examples:

The book is on the table. (sobre)

The book is beneath the table. (abajo, debajo)

The book is leaning against the table. (contra)

The book is beside the table. (al lado, junto a)

She held the book over the table. (sobre)

She read the book during class. (durante)

In each of the preceding sentences, a preposition locates (una preposición localiza o ubica al noun -book-) the noun "book" in space or in time. (en el espacio o tiempo)

http://www.uottawa.ca/academic/arts/writcent/hypergrammar/preposit.html

IN

Use 'in' months and years and periods of time:

• in January
• in 1978
• in the twenties

Use 'in' a period of time in the future:

• in a few weeks
• in a couple of days

AT

Use 'at' with precise time:

• at six o'clock
• at 10.30
• at two p.m.

ON

Use 'on' with days of the week:

• on Monday
• on Fridays

Use 'on' with specific calendar days:

• on Christmas day
• on October 22nd

IMPORTANT NOTES

in the morning / afternoon / evening - at night

We say in the morning, afternoon or evening BUT we say 'at night'

 

Test Your Understanding

Now that you have studied the use of in / at / on - prepositions of time and date, try the follow-up quiz to test your understanding.

Prepositions of Time and Date Quiz (ejercicios con preposiciones de tiempo)
Excercises using Prep. of Time


http://esl.about.com/od/grammarintermediate/a/prepositions_of_time.htm