A. in
in bed / in hospital / in prison / in a street
in the sky / in the world / in a newspaper / in a book / in a photograph / in a picture / in a car / in a taxi / in the middle (of ...)
• 'Where's Kate?' 'She's in bed.'
• David's father is in hospital.
• I live in a small street near the station.
• I like to look at the stars in the sky at night.
• What's the longest city in the world?
• I read about the accident in the newspaper.
• You look sad in this photograph.
• Did you come here in your car?
• There's a big tree in the middle of the garden.
B. at
at home / at work / at school / at university / at college
at the station / at the airport / at Jane's (house) / at my sister's (house) / at the doctor's / at the hairdresser's etc.
• Will you be at home this evening?
• 'Where's Kate?' 'She's at work.'
• Helen is studying law at university.
• Do you want me to meet you at the station?
• 'Where were you yesterday?' 'At my sister's.'
• I saw Tom at the doctor's.
Often it is possible to use in or at for buildings (hotels, restaurants etc.):
• We stayed at a nice hotel. or We stayed in a nice hotel.
C. on
on a bus / on a train / on a plane / on a ship
on the ground floor / on the first floor etc.
on the way (to ...) / on the way home
• Did you come here on the bus?
• The office is on the first floor. (not 'in the first floor')
• I met Ann on the way to work / on the way home.
in
in bed
in hospital
in the sky
in a car
at
at home
at work
at university
at the doctor's
on
on a bus
on the first floor
on the way home