Veja as frases abaixo:
- She arrived at 3 o'clock
- She arrived on Sunday
- She arrived in May. She arrived in 2005.
Assim devemos usar:
- at para as horas: at 4 o'clock, at 11.30, at midnight, at lunchtime, at sunset etc.
- on para datas e dias: on 25 April 2007, on Christmas Day, on my birthday, on Friday(s).
- in para períodos longo: in May, in 2005, in the 21st century, in (the) summer, in (the) future.
Não se usa at/on/in antes de last, next, this, every:
- I will be there next Sunday(e não on next Sunday)
- He was hired last March.
That's all for now folks. Enjoy your studies.