▲本题的答案确实应是填 on。句意为：他不止一次因粗心大意而受到责骂。more than one 的意思是“不止一……”。如：

More than one person is involved in this. 与此事有牵连的人不止一个。

More than one student has read the book. 不止一个学生读过这本书。

There is more than one way to tackle the problem. 解决这个问题不止一个办法。

Some problems have more than one legitimate solution. 有些问题不止有一个合理的解决方法。

▲如果一定要填 much，可考虑这样改一下：

He was scolded for his carelessness ______ more severely on more than one occasion.

这样一改，也可以填 much，此时的 much 修饰比较级 more severely。句意为：他不止一次地因粗心大意而受到严厉得多的责骂。