单选题 Without the music, the children would have not had so much fun.

【正确答案】 D
【答案解析】[解析] 当有两个以上的助动词时,not跟在第一个助动词之后。介词短语without the music可代替虚拟条件从句;本句表达的是与过去事实相反的假设,后面的主句谓语应用would+have+过去分词;因此选项D为答案。