Faced with unethical demands, he would sooner quit his job than violate his moral code.

would 在这里表示"宁愿"的意思，用于表达意愿或选择。 sooner 是 soon 的比较级形式，原意是"更快、更早"，在这里与 would 搭配构成 would sooner 短语，表示"宁愿、宁可"。 would sooner 是一个固定搭配，意思是"宁愿...也不愿..."，用于表达在两种选择中更倾向于前者。