Ответ:

Время указываем с at, месяцы и времена года — с in, дни недели — с on. Устойчивое выражение: at the weekend.

  1. She gets up at 7 o’clock.
  2. My mum’s birthday is in July.
  3. We go to the sea in summer.
  4. Ann goes to music lesson on Fridays.
  5. I visited my granny at the weekend.