Answer (EN)
- Marina is at 1) the seaside now. She is having 2) a lot of fun. In 4) the morning she is going to make 5) a sandcastle and play with 6) her friends. In 7) the afternoon she is going to have
Translation (RU)
- Марина сейчас на 1) море. Она веселится 2) много. 4) Утром она собирается построить 5) замок из песка и поиграть с 6) друзьями. 7) Днем она будет
Brief explanation: We use 'the' when referring to something specific or generally known (like 'the seaside', 'the morning', 'the afternoon'). We use 'a' before a singular countable noun when it's not specific (like 'a sandcastle'). 'Her friends' is a possessive phrase.