As in many languages, prepositions are perhaps the most difficult part of grammar to learn because direct translation is often impossible. Prepositions can be translated differently depending on the situation or context of their use. It is therefore recommended that the student memorize the different types and uses of the various prepositions, depending on their relationship to the object in the sentence (place, time, movement/direction). As we will see, many of the prepositions can be used in various contexts (place, time or movement/direction).
Note: Prepositions are always followed by a noun, not a verb (except in the gerund form).
In / At / On
Among the most common prepositions are “in”, “at”, and “on”. These three prepositions can be used to indicate either place or time.
Use (place): “In” is used to indicate both open and closed spaces. We use this preposition to indicate that something is included within the limits of something, a closed space or the interior of something in a physical sense. As we can see from the following examples, “in” can also be used to indicate the geographical location of something.
Use (time): “In” is used with months, years, periods of time, seasons and parts of the day.
Use (place): “At” is used in front of buildings such as “home”, “the airport”, “university”. It is also used before “top”, “bottom” and “the end of”, as well as to indicate events such as meetings, parties, concerts, sports events, etc. “At” is also used after the verb “arrive” when we are referring to places other than cities or countries.
Use (time): We use “at” before the hour or holidays.
Use (place): “On” is used with surfaces, when we are referencing a location within a room, such as the ceiling or the wall, or to indicate that someone is inside a mode of transport or on the floor of a building.
Use (time): “On” is used with days of the week, dates and holidays.