 The prepositions of time, at, on, and in. The prepositions of time describe when something happens, happened, or will happen. What exactly is the different between these three prepositions? Let's have a look below. When do we use at? We use it for a specific time or hour of the day, for example, at 10 AM, I get up at 10 AM on Sundays. At midnight, the fireworks appear at midnight on New Year's Eve. At is also used for a holiday period or a festival, such as, at Christmas, we always sing carols at Christmas. At Thanksgiving, my aunts come and visit us at Thanksgiving. When do we use on? We use on for specific days, for example, on Monday, I have a doctor's appointment on Monday. On Wednesday, she always goes grocery shopping on Wednesday. On Christmas Eve, we had a huge holiday family dinner on Christmas Eve. We also use on when talking about dates, for instance, on May 20. My brother celebrates his birthday on May 20. On December 25, we always visit my grandparents on December 25. When do we use in? The preposition in is used with months, for example, in February, my birthday is in February. In September, we are moving house in September. The preposition in is also used with years, for example, in 1789, the French revolution began in 1789. In 1992, I was born in 1992. The preposition in is also used with decades, such as here, in the 1960s, the Beatles were the most popular band in the 1960s. In the 1920s, many western cities experienced a time of economic prosperity in the 1920s. The preposition in is also used with centuries, such as, in the 17th century, Louis XIV was a French king in the 17th century. In the 21st century, we are living in the 21st century. When talking about seasons, we also use the preposition in. For example, In winter, we love to go skiing in winter. In spring, I love when all the flowers bloom in spring. When talking about a period of time, we also use the preposition in. For example, In four hours, she completed the whole marathon in four hours. In ten years, she wants to travel the world in ten years. For parts of the day we also use in, such as, In the morning, I always have a cup of coffee in the morning. In the evening, she wants to go out for dinner in the evening. Note that we say it night and not in night. This is a special exception to the rule. At the weekend or on the weekend? The word weekend has either at or on as a preposition. Typically in British English, people say at the weekend, and in American English you will much more often hear on the weekend. Thanks so much for watching. We are ITTT, the leading provider for Teflon TESOL training courses. If you liked this video, please subscribe by clicking that button down here and click on any of the videos here on the left for more interesting teaching tips for getting certified to teach English abroad and online.