IELTS Speaking: correct the mistakes

 Here are some sentences that people wrote below last Friday's speaking lesson. Can you find and correct the mistake(s) in each one?

1. I am gonna tell you about a book center at the downtown.
2. It was a marvellous experience that I wish I could repeat it soon.
3. At last, I feel that the staff are quite responsible.
4. Initially, everything was ok, no special.
5. That's my first time visited church.