Написать письмо, не из учебника. Не каким либо персонажем, а так как в реальности человеку, ну думаю вы поняли)

Hello Liza,

Greetings from Saint-Petersburg! I'm having the time of my life! I have been to Saint-Petersburg for three weeks.

I've seen a lot of attraction and been in Nevsky Prospect. My family and I have been in Hermitage. Together we've gone souvenir shopping, seen famous landmarks. Sain-Petersburg is amazing!

See you in three days. Take care!

Love, Sergei.