I had no idea the concert was this week ! I though it was next week...
I was completely mistaken and thought the concert was next week.
I thought the concert was next week !
"コンサートは来週だと思ってた"
I had no idea the concert was this week ! I though it was next week...
コンサートの日が今週だったと全く知らなかった!来週だと思ってた...
I was completely mistaken and thought the concert was next week.
コンサートは来週だと思っていて,完全に間違えた.