They said the allegations related to an isolated case of cheating.

他们说这些指控与一件孤立的欺诈案有关。

It could be only an isolated case.

这有可能只是一个孤立事件。

Hopefully this is an isolated case.

希望这只是非全面性的单一各案。

Is this an isolated case?

这是否是一个孤立的事件？

This is not, after all, an isolated case.

毕竟，这不是一个单独的事件。