YOU SAID:
I am gonna have to go to some stupid band concert tomorrow.
INTO JAPANESE
私は明日バカバンドコンサートに行かなければならないつもりです。
BACK INTO ENGLISH
I will have to go to a stupid band concert tomorrow.
INTO JAPANESE
明日は愚かなバンドコンサートに行かなければならないでしょう。
BACK INTO ENGLISH
I will have to go to a stupid band concert tomorrow.
You've done this before, haven't you.