Prepositions show the relationships between the ideas, nouns, and verbs within a sentence. Mainly, prepositions show this connection via time, location, or purpose. Some prepositions, such as behind, above, before, and against, have somewhat straightforward uses – for example, behind pretty much always means the same thing.
However, the common prepositions in, on, and at can be tricky to use because they seem and look similar to each other. When do you use in instead of at, or on instead of in?
In, on, & at: General to Specific
In most cases, in→on→at go from general→specific, in that order. In typically refers to the most general time frames and spatial areas, while at usually refers to the most specific.
Time and in, on, & at
In refers to larger time frames: historical eras, long time periods, centuries, decades, years, seasons, months.
- People didn’t survive long in the Ice Age.
- The Black Plague occurred in the middle ages.
- Life was different in ancient times.
- Christopher Columbus sailed the ocean blue in 1492.
- He’ll be headed back in spring.
- Christmas falls in December.
*Exception: Also use in to refer to general times of day, such as in the morning, or in the evening.
On refers to semi-specific time frames, such as days and dates, and general times on specific days.
- He will arrive on December 23rd.
- The Giants will play the Dodgers on September 8th.
- Can you believe Thanksgiving is on Thursday?
- I think that party fell on a Friday.
- Can you please host the party on a weekend?
*Note the use of on for general times on specific days.
- Will you get here on Tuesday morning?
- She will leave on Thursday afternoon.
At refers only to specific and precise times.
- We will meet at sunset.
- Our family eats dinner at 6:00 every night.
- I walk my dog at sunrise and at dusk.
- We play football at noon.
- You should already be showered at bedtime.
*Note the use of at for night, morning time or nighttime.
- We only come out at night.
- We hear some spooky sounds at nighttime.
Location and in, on, & at
Just like with times, locations for in→on→at go from general→specific, in that order. The most general, unspecified locations use in, and at refers to the most clearly specified points.
In refers to the larger or more general locations and places: the universe, the world, continents, countries, states, cities.
- I live in this universe.
- She lives in a different world.
- My Dad is currently in Antarctica.
- Wait, are you in California right now?
- The Golden Gate Bridge is in San Francisco.
On refers to semi-specific places like islands, streets, large vehicles (airplane, boat, train), and surfaces (the table, the floor, the beach, cement, etc.).
- I have a house on the big island in Hawaii.
- We had a club sleepover on an aircraft carrier ship.
- My family lives on Cedar Avenue.
- You can put the cooler down on the kitchen floor.
- Let’s go play football on the grass.
At refers to the most specific places, including street addresses, specific locations, and exact points.
- The party will take place at 5402 Walton Street.
- Come meet me at home.
- Tonight, there will be a sleepover at my house.
- I’m at the Washington Monument right now!
- The man will meet you at the corner of Alpine Road and Washington Street.
In, on, & at, some of the smallest words in the English language, can also be the trickiest. But if you keep in mind the rule that in refers to the most general, on refers to the semi-general, and at refers to the most specific, you’ll be on your way to mastering the minute differences between these prepositions. Get writing, and enjoy the process.
