Prepositions of Time: In, At, On

In: Can be used for months, years, decades, centuries, seasons, and the future.

Examples:

1.) I will go to university in September.

2.) I went to university in 1993.

3.) I went to university in the 1980’s.

4.) I went to university in the late 20th century.

5.) I go to university in the fall.

6.) I will go to the store in a few minutes. Note that this use of “in” is in the future, but it is for a shorter period than the other examples.

At: Can be used for particular times.

Examples:

1.) I will go to the store at 5:30.

2.) I go to the store every day at midday.

3.) I go to the store on Tuesdays at lunchtime.

4.) I go to the store at sunset.

5.) I go to the store at night. Note that we do not say “at day.” Instead, we say, “during the day.”

6.) I go to the store at Thanksgiving to buy enough food for the meal.

7.) British English usage: I go to the store at the weekend.  American English would say, “on the weekend.”

On: Can be used for days and dates

Examples:

1.) I like to go to parties on Fridays.         

2.) I am excited to go to the party on January 19.

Reference:

http://www.englishgrammarexpress.com/grammar/in-on-at-time

Check out these sites for some online practice! Then try making your own sentences using these prepositions.


http://www.perfect-english-grammar.com/time-prepositions-exercise-2.html

http://www.englishexercises.org/makeagame/viewgame.asp?id=5278