I made a promise to myself this year my first year in high school would be different.(20

问题补充：

I made a promise to myself this year，my first year in high school，would be different.(·浙江)

A. whether

B. what

C. that

D. how

答案：

A. whether

B. what

(答案→)C. that

D. how

解析：此处是that引导的同位语从句，用来解释说明a promise的具体内容，同时从句中不缺少成分，且句意完整，所以用that引导。故选C项。