http://kyounojanaru.com/language-it-has-been-decided-and-to-decide-on-%e3%80%9c%e3%81%93%e3%81%a8%e3%81%ab%e3%81%aa%e3%82%8b-%e3%80%9c%e3%81%93%e3%81%a8%e3%81%ab%e3%81%99%e3%82%8b/
LANGUAGE: How to use 'It has been decided' and 'I decided on' - 〜ことになる | 〜ことにする JLPT N4