Kneeling down on a long bench in front of the platform in classroom, Li Yuanfang has been teaching since 2008.

Li is a female teacher suffering from pains in her legs at a village primary school in east China's Anhui province. 

Li,42, was diagnosed with polio at the age of three. Li pursued her study as normal kids and went to university. In 1998, she started her career as a primary teacher after graduation. 

Li teaches four classes and oversees her students in a one-hour self-study program every day, meaning she is present in front of her students for nearly four hours a day.

At first, Li used a crutch. In 2008, she suffered from severe scoliosis because of use of a crutch for such a long time in her classrooms. To relieve the pain in her legs and waist, she has been on one knee or both knees ever since.

Despite her suffering, Li tries her best to work out ingenious methods to help her students — many of them being left-behind children — get rid of bad habits and grow happily.