For example, when discussing the differences between men and women, Dong asked whether women could be police officers. "Some students said that girls can't become police officers," he recalled.

This made Dong think deeply about whether short-term volunteer teaching could help rural students gain a good understanding of gender equality. In subsequent classes, he gave more examples to help them understand the concept, such as asking if their mothers did most of the housework and whether their fathers ever helped with daily chores.

"They answered that their fathers might not be home often, but if they were at home they didn't do any housework," he said.

Dong believed that compared with giving a lecture on the different bodily structures of men and women, the concept was easier for the primary school students to accept as they were more willing to speak up and make points in class.

"And it (expressing views) is also an important part of education," he said.