Tricky Prepositions

At, in and on

It is difficult to learn rules for at, in and on because there are so many exceptions, but here are some guidelines to help you.

We use at to refer to a place or an event:

I am at the bank. (Place)
She is at the doctor’s. (Place)
He is sitting at his desk. (Place)
The train will stop at the next station. (Place)
I will be at home when you call. (Place)
She is at her parents’ house. (Place)
I work at XYZ (Place)
I met her at a party. (Event)
We won’t have a stand at the trade fair this year. (Event)

In can mean “inside” “within” or “into”:

I am in the bank at the moment. (Inside the bank)
We are in the meeting room. (Inside the meeting room)
My sister lives in London. (Within the borders of London)
I read it in the report. (Within the report)
I can see it in the picture. (Within the picture)
Please get in the car. (Into the car)

Here are some other examples of in:

I like living in the countryside.
I like walking in the rain.
The children are playing in the street.

On can mean “on top of”:

The book is on her desk. (Compare with: She is sitting at her desk)

We use on for certain media:

I saw it on television. (Also for specific programmes e.g. I saw it on the news)
I read it on the Internet.
I heard it on the radio.

Here are some other examples where we use on:

The station is on the left.
The picture is hanging on the wall.
You can see it on the screen.
His office is on the 24^th floor.

Time

We use at with specific times, festive seasons and points in time:

The meeting is at 9:00 am. (Specific time)
I’m having lunch at midday. (Specific time)
I’m visiting her at Easter. (Festive season)
At the time she was still working at XYZ. (Point in time)
I’m going there at the weekend. (UK) (Point in time)
It’s very quiet at night. (Point in time) (Compare with: In the morning, in the afternoon, In the evening)

We use in with months, years, seasons and parts of the day:

She started in January. (Month)
The company was founded in 1993. (Year)
We’ll hold the party in the summer. (Season)
Let’s hold the meeting in the afternoon. (Part of the day) (Compare with: At night)

We use on with days and dates:

The meeting is on Monday. (Day)
I’m going there on the weekend. (USA) (Days)
I’ll call her on her birthday. (Day)
Her birthday is on 25 September. (Date)

For and Since

For is used with a period of time and can be used with different tenses.

Since is used with a point in time and is used with the present perfect.

For

I worked in my last job for five years.
I am going on holiday for two weeks.
I have been living here for three months.

Since

I have been living here since March.
I have been on holiday since Wednesday.
I have been waiting since 9:00 am.

By and Until

By is used for an action or event that takes place before a specified deadline. The event or action can take place before the deadline or on the deadline at the latest.

Until is used for an action or event that takes place over a specified period of time. It lasts for the whole of that time.

Please send me the report by Friday.
Can you call me by 25 August, so I know what’s going on.
I’d like you to arrive by 10:00 am, so that we can start the meeting on time

Until (or till)

The meeting starts at 10:00 am and lasts until lunchtime.
His contract runs until the end of the year.
Could you keep checking Sarah’s emails until she gets back from holiday.

Ago and Before

Ago describes how far back in the past something happened.

Before describes when an action or event took place in relation to another action or event.

Ago

She changed her job six weeks ago.
The situation was a lot worse a year ago.
I started my current job twenty years ago.

Before

I always drink a cup of coffee before I start work.
Can you switch the lights off before you leave the office.
Can you speak to me before you speak to her.

During and While

Both during and while show parallel actions or events.

During is a preposition so it is followed by a noun, which often represents the action itself.

While is a conjunction so it is used at the start of a complete sentence (or part of a sentence).

During

I fell asleep during the presentation.
During the phone call it became clear to me that my boss was angry.
I drank too much coffee during the meeting.

While

I fell asleep while he was giving his presentation.
While I was talking to my boss, it became clear to me that he was angry.
My computer shut down while I was away from my desk.