1. Prepositions of Time

Prepositions of time

Prepositions of time help indicate when ; i.e., the time and date, month, season, year, decade, century, period, age (e.g., stone-age, iron-age), millennium, epoch, deep-time periods (e.g., cretaceous, holocene), or the period of time that something happens.

Some of the prepositions used include:

around  at  by  during  from  in  on  since  throughout  until  before  after  between

Quick guide (common patterns)

Patterns:

  • at + time: at 7:30, at noon, at midnight
  • on + day/date: on Monday, on April 2
  • in + month/season/year/decade/century/period: in May, in 2025, in the 1800s, in the Holocene
  • during / throughout + span: during the test, throughout the year
  • from ... to / until : from 9 to 11, until Friday
  • since + start (still true now): since 2010, since last week

1. Exact points in time (clock time & specific moments)

Use: at , around , by

  • The lesson starts at 9:00 a.m.
  • Please call me around noon.
  • Be home by 10 p.m.
  • The bus arrived at midnight.
  • The report should be finished by Friday morning.

2. Dates & days (calendar time)

Use: on + day/date; at (some holidays); by (deadline)

  • We have class on Monday.
  • The meeting is on March 12.
  • She arrived on the first day of school.
  • We open presents at New Year.
  • Send it by Monday (deadline).

3. Months, seasons, years, decades, centuries, and longer blocks

Use: in + month, season, year, decade, century, millennium

  • School starts in September.
  • It rains a lot in the rainy season.
  • He was born in 2009.
  • Many trends changed in the 1990s.
  • Air travel grew quickly in the 20th century.
  • Computers became smaller in the 21st century.
  • Some civilizations developed writing in the 3rd millennium BCE (Before Common Era).

4. Time spans (duration: how long something happens)

Use: during , throughout , for (duration)

  • I felt nervous during the exam.
  • The lights stayed on throughout the night.
  • He slept throughout the lecture.
  • They traveled during the holiday break.
  • She lived there for three years.

5. Start → end (from one time to another)

Use: from ... to ; until (end point)

  • We work from 8 a.m. to 5 p.m.
  • The store is open from Monday to Saturday.
  • Wait here until I come back.
  • The museum is closed until July.
  • They practiced every day from January to May.

6. “Since” (start time that continues to now)

Use: since + starting point (still true now)

  • I have lived here since 2018.
  • She has been busy since Monday.
  • They have known each other since childhood.
  • The bridge has been closed since last week.
  • He has studied English since he was ten.

7. Relative time (before/after & order of events)

Use: before , after , by (no later than)

  • Wash your hands before dinner.
  • We went for coffee after class.
  • Please finish before you leave.
  • By the time we arrived, the movie had started. (no later than)
  • After the storm, the streets were quiet.

8. Historical periods, ages, and deep time

Use: in (period), during (events within a period)

  • Early farming developed in the Neolithic period.
  • People used bronze tools in the Bronze Age.
  • Dinosaurs lived during the Cretaceous period.
  • Modern humans spread widely during the Late Pleistocene.
  • Sea levels changed in the Holocene epoch.
  • Many species went extinct at the end of the Cretaceous.