Prepositions are a necessity to form a sensical sentence. They connect the subject to the predicate or the parts of the predicate itself to each other.
In
In the news
In a hurry
In troubles
In a mess
In a flash
In the air
In advance
In a deep sleep
In a heap
In abundance
In action
In return
In mind
In pain
In a state of Euphoria
In touch
In abeyance
In addition to
In time
In full
I was in the classroom when the teacher came.
They were in big trouble.
Sam enjoyed the trip in 2008 more than any other.
Groups of people joined in when they heard their help is required.
The pastor was in horror when he found about the father’s horrific actions.
On
On good terms
On Oximan Street
On the phone
On TV
On leave
On the page
On a plane
On paper
On the brink of
On the edge of
On such a cold day
On a warm day
On loan
On the menu
On the roof
On impulse
On occasions
On guard
On strike
On the agenda
On the outskirts of
On the dot
On-demand
On a diet
On suspicion of
On a short notice
All travelers should be on time for their flights.
Work is best done on schedule.
Joan forgot her lunch on the table.
The FBI agent was on oath during the trial.
My sister goes on a shopping spree whenever she has money.
At
At random
At that time
At bedtime
At all costs
At all events
At 5:00 p.m.
At midday
At Christmas
At dinner
At heart
At length
At once
At the same time
At sunset
At the age of
At face value
At first
At first sight
At the top of
At last
At dusk
At play
At a low ebb
At one’s request
At one’s demand
At ease
At the peak of
At war with
At an advantage
At the hands of
Those kids are at risk.
We should help the people at least when we can.
Any problem at large can be solved with enough time and planning.
It is not a wise choice to go out at night when you are sick.
If you fight a person who has nothing to lose, you are fighting at a loss.
This may be able to sum it up all in a simple way. In is used to describe a place that has no boundaries, for example, “the living room is in the basement.” On is used to describe something that exists on top of something else, for example, “my desk is on the floor.” At refers to the time of day, for example, “we had lunch at noon.
Prepositions are often forgotten about when it comes to grammar, but they can make a huge difference in your writing. If you’re not sure what prepositions are, take a look at this article to see what they are and how they can be used.