I made a promise to myself______ this year, my first year in hig

I made a promise to myself______ this year, my first year in high school, would be different.
A、whether
B、what
C、that
D、how
【正确答案】：C
【题目解析】：that引导同位语从句，在从句中不做句子成分，补充说明同位语promise的内容。