单选题 John is very diligent, but his pay isn't {{U}}sufficient{{/U}} enough for his work.
【正确答案】 A
【答案解析】[分析] 结构应用 本句意为：约翰非常勤勉，但就他的工作而言，他的薪水可不够多。本句的系表结构应是指他的薪水不够多/好：his pay isn't good，而enough是程度副词，它一般放在它所修饰的形容词或副词之后；例：good enough，warm enough等等；因此A为答案。