Prepositions (before nouns)

Prepositions (before nouns)

Some nouns form fixed combinations with certain prepositions if used in specific contexts:

Example (1): Sound at a distance of 400 metres downwind is virtually inaudible.
‘… at a distance …’
Example (2): We measure noise at all different frequencies.
‘… at frequencies’
Example (3): Wind speeds must stay at levels of around 6 to 8 m/s.
‘… at levels …’
Example (4): Noise levels are averaged at a wind speed of 5 m/s.
‘… at a speed …’


Use ‘at’ to form a prepositional phrase with the nouns

  • ‘distance’, as in Example (1),
  • ‘frequency’, as in Example (2),
  • ‘level’, as in Example (3),
  • ‘speed’, as in Example (4)

More examples

Example (5): It’s important to get the parts in time.
‘… in time’
Example (6): We’ll have to take the generator off line.
‘… off line’
Example (7): We give planning permission on (the) condition that criteria are met.
‘… on (the) condition …’
Example (8): We observed operation on a morning with wind speeds around 9 m/s.
‘… on a morning …’

Use the specific prepositions with nouns such as:

  • ‘in time’ or ‘on time’, meaning ‘punctually’, as in Example (5),
  • ‘off line’, meaning ‘not operative’, as in Example (6),
  • ‘on (the) condition’, meaning ‘provided that’, as in Example (7),
  • ‘on a morning’, when referring to the first half of a day, as in Example (8),
    but ‘in the morning’, referring to any morning,
  • also: ‘in the afternoon/evening’,
    when referring to the second half of the day.