Stop saying: “We have a test in Monday.”
Say instead: “We have a test on Monday.” · A2 · Prepositions
✗ Wrong
We have a test in Monday.
✓ Correct
We have a test on Monday.
Why?
Use on with days and dates: on Monday, on Friday, on May 12. Use in with months and years: in July, in 2026. Use at with clock times: at 9 o’clock.
More examples
🎙️ REAL VOICES
The three correct examples below, in a real voice.
✗ The meeting is at Friday afternoon.
✓ The meeting is on Friday afternoon.
✗ I will see you in Tuesday.
✓ I will see you on Tuesday.
✗ Her birthday is in May 12.
✓ Her birthday is on May 12.
Days wear on — on Monday, on Tuesday, on every date.