一道关于反义疑问句的英语题！

填 did they?

No one showed...可理解为= They didn't show....
前否定，后肯定

did he （NO ONE 表示否定，故用肯定）

did it？

6.陈述部分的主语是 everybody, everyone, anybody, anyone, somebody, someone, nobody, no one, none, neither 时, 其反意疑问句的主语需用复数代词they。
Everyone is here, aren't they? 大家都到了，是吗？

No one knows about it, do they? 没有人知道这件事，对吗？

所以答案是[did they].

did they?
原句等于They didn't show any interest in this new film,did they?

did they
或者 did he/she

no one 是个含否定意义的复合不定代词，一般用they或者he/she替代。