In, On, At (Expressions of Time)

In = Period of Time, Year, Season, Month, Part of Day

• I went to school in the past.
• I went to school in the summer.
• I went to school in 1974.
• I went to school in March.
• I went to school in the morning.

On = Specific Day, Specific Day + Part of Day

• I went to school on March 10th.
• I went to school on Tuesday.
• I went to school on Tuesday afternoon.
• I went to school on the morning of March 10th.

At = Specific Time, Specific Time + Day

• I went to school at 10:00.
• I went to school at noon yesterday.
• I went to school at noon.
• I went to school at two o’clock.

Animation by Koon Wei Ho