1. At

We use “AT” when we show time:
at three o’clock at sunrise at night

And in next expression:
at midnight | at the New Year | at the time | at the appointed time | at the beginning |
at the end | at the week | at the weekends | at five o'clock | at 11.45 | at sunset | at moment | at presant | at night | at the same time

Example:
- At weekends there is a lot of traffic on the roads.
- I don't like going out at night.
- Do you give each other presants at Christmas?
- Emily and I arrived at the moment / at presant.

2. On

We use “ON” with calendar’s date and days.
on Boxing Day | on Christmas Day | on the 21 of May | on the first of November | on Friday | on 16 May 1999 | on me birthday

And in next expression:
on a rainy day (morning, night) | on somebody’s arrival
on the appointed day | on the eve of smth on the occasion

Example:
On Monday we go to school.
On Sunday we stay home.

3. In

We use “IN” with long part of time (months, seasons, years):
in September | in October | in the 21 century | in 1968 | in the 1970s | in the past |
in the early (late) 30s | in the Middle Ages
or
in the morning | in the afternoon

We also use “IN” in order to say how soon something will happen:
in half an hour | in a month.

Example:
I'll see you in the morning.
Do you work in the evening.

We say:

In the morning(s)
In the afternoon(s)
In the evening(s)

but

on Friday morning(s)
on Sunday afternoon(s)
on Monday evening(s)
etc.

1. We not use at/on/in before words:
next and last:

Example:
I'll see you next morning.
It didn't rain last month.

2. In spoken English we often leave out "ON" before days (Sunday, Monday)

Example:
I'll see you on Friday or I'll see you Friday.

3. In a few minutes / in six mounths ets.

The train will be leaving in a few minutes.
Andy has gone away. He'll be back in a week.

4. You also say "In six months' time", "In a week's time" etc.

They're getting married in six months' time.

5. We also use in ... to say how long it takes to do something.

I learnt to drive in four weeks.

1.
in a room
in a building
in a box

2.
in a garden
in a town/country
in the city centre

3.
in a pool
in the sea
in a river

Examples:

1. There's no-one in the room /in the building / in the garden.
2. What have you got in your hand / in your mouth?
3. When we were in Italy, we spent a few days in Venice.
4. I have a friend who lives in a small village in the mountains.
5. There were some people swimming in the pool / in the sea / in the river.

at the bus stop
at the door
at the window
at the roundabout
at reception

Examples:

1. Do you know that man standing at the door / at the window?
2. Turn left at the traffic lights / at the church / at the roundabout.
3. We have to get off the bus at the next stop.
4. When you leave the hotel, please leave your key at reception.

1. on the wall / on the ceiling / on the door / on the table / on the floor

2. on the nose

3. on a page

4. on an island

Examples:

1. I sat on the floor / on the ground / on the grass / on the beach / on a chair.
2. There's a dirty mark on the wall / on the ceiling / on your nose / on your shirt.
3. Have you seen the notice on the board / on the door?
4. You'll find details of TV programmes on page seven (of the newspaper).
5. The hotel is on a small island in the middle of the lake.

1. There were a lot of people in the shop. It was very crowded.
Go along this road, then turn left at the stop.
2. I'll meet you in the hotel lobby.
I'll meet you at the entrance to the hotel.

There is some water in the bottle.
There is a label on the bottle.

There is somebody at the door. Shall I go and see who it is?
There is a notice on the door. It says "Do not disturb".