感谢您的建议.他们都没有工作，但我找到了解决方案.

Thanks for your suggestions. None of them did work but I found a solution.

df = pd.read_excel(r'./../B_folder/2_file.xlsx')

这对我来说很好用.

因此，如果有人遇到相同的问题，希望对您有所帮助.

So if anybody faces the same problem, I hope this helps.