Prepositions of Time 

• in → months, years, seasons, parts of the day (except night)
  Example: I was born in July.
• on → days, dates
  Example: My birthday is on Monday.
• at → exact times, night, specific moments
  Example: We eat dinner at 7 o’clock.

• During → something happens within a period of time.
• Throughout → something happens for the whole duration of that period.
  
  

• She fell asleep during the lecture. (At some point in the lecture.)
• It rained throughout the night. (The rain continued for the whole night.)

• By → before a specific time (deadline).
• Until / Till → up to a certain point in time.
  
  

• I have to finish my homework by 6 p.m. (Finish before 6 p.m.)
• She waited until 7 o’clock. (She waited up to 7 o’clock.)
• They stayed at the party till midnight. (Stayed up to midnight.) 

• I work from 9 a.m. to 5 p.m. (The work period starts at 9 a.m. and ends at 5 p.m.)
• The museum is open from Monday until Friday. (The museum is open continuously from the start of Monday to the end of Friday.)

• For → shows duration, how long something lasts.
• Since → shows the starting point of an action.
  
  

•  I have lived in London for three years. (Duration: three years.)
• She has been studying English since 2020. (Starting point: 2020.)
• We have been waiting for 30 minutes. (Duration.) 
  
  

• Ago → from now, in the past.
• Before / Earlier → comparing events in the past.
• Later / Afterwards → comparing events in the future.
  
  

• He left the office two hours ago. (Two hours before now.)
• I met him earlier this week. (Before another point in the same week.)
• She will call us later today. (After now, still today.)
• They arrived after the meeting finished. (After another event.) 
  
  

• Use at for exact times and night: “The party starts at 8 p.m.”
• Use in for parts of the day, months, seasons, years: “I usually exercise in the evening.”
• Use on for days and dates: “We met on Monday.”
  
  

• Since → from a starting point in the past: “She has lived here since 2020.”
• For → duration: “I studied for two hours.”
• Ago → time from now in the past: “I left an hour ago.”
  
  

• Before → earlier than a point: “Finish your homework before 6 p.m.”
• After → later than a point: “We can meet after class.”
• Until / Till → up to a point: “I waited until 7 o’clock.”
• By → not later than a point (deadline): “Submit your work by Friday.”

• in → long periods: months, years, seasons, parts of the day
• on → specific days or dates
• at → exact times, night
• during / throughout → inside a period
• until / till / by → deadlines or limits
• for / since → duration or starting point
• ago / before / after / later → relative past/future