What part of speech did Fan Ji use flexibly?

"Fan Ji" is a noun and is used as an adverbial here. It means: use a dustpan. Dustpan (jρběn): dustpan, an instrument made of bamboo or wicker. This means putting mud and stones in a dustpan.

Source: Rain Lee, the author of "A Mountain of Yugong"? pre-Qin period

Then lead the children and grandchildren to take charge of Sanfu, knock on the stone and cultivate the soil, and transport it to the end of Bohai Sea. Shi Jing, my neighbor's widow, had a man, so she began to help him. Cold and summer are easy to celebrate, and the beginning is the opposite.

Interpretation of vernacular:

So Gong Yu led three children and grandchildren who could carry the burden up the mountain, chiseled stones and dug dirt, and transported them to the Bohai Sea with a dustpan. Neighbor Shi Jing's widow has an orphan, only seven or eight years old, skipping to help him. Winter and summer change seasons, and you can go back and forth once.

Creative background:

The Warring States period is a period of great social change, and it is also a period of academic thought contending. Fable, as an important part of the essays of the philosophers, has become a powerful weapon for the philosophers of the Warring States to clarify their political views, academic thoughts and arguments. Liezi is a collection of fables and fairy tales created under this background.

This article tells the story of Gong Yu who dared to dig a mountain and finally moved the Emperor to move it away. It also shows that under the condition of extremely underdeveloped productive forces at that time, people can only fantasize about conquering nature with the help of a god with superhuman strength. As the earliest collator and annotator of Liezi, Zhang Zhan thought Liezi was not an ancient book in the pre-Qin period.

In Zhang Zhan's view, Liezi contains a lot of Buddhist thoughts, and language and stories are the carriers of thoughts, which means that some texts of Liezi are related to Buddhist scriptures. The story of "Yu Gong Yi Shan" originated from Zhu Fahu's translation of the Buddhist scripture "One Mountain". The myth of different mountains is a common story in Buddhist scriptures in the Middle Ages, and the founder of Liezi has systematically read the translation of Fahu.