单选题 A promising note is a written agreement to pay a certain sum of money at some time future.

【正确答案】 D
【答案解析】[解析] 此处要注意语序：时间状语是at...time，如：at this (that) time在这(那)时；future在此是形容词“未来的，将来的”，作time的定语；因此选项D是答案。