"I believe through such daily practice, students can have a good foundation on which they can improve their English-language abilities in listening, speaking, reading and writing, and thus improve their English proficiency," Du says.

She also says she has made more than 1,500 classes on social media platform Sina Weibo, enabling students to learn English for two to three consecutive years.

"The lessons can help a student with zero knowledge in English learn until they can read English easily," she says. "In future, I will make more such lessons to help them continue improving various English abilities, and finally form a learning system that enables students to achieve a high level of English proficiency."

Nearly 320,000 people follow Du on Weibo, and some people show her their progress in the form of videos. Sometimes, Du responds to them by giving them suggestions.

"I used to feel anxious as I couldn't find a proper way to make my children start learning English, but Du gave us some effective suggestions," says Sina Weibo user Ningmengxiaoxian'er, a mother of two children from Laixi in Shandong province. "Although my children don't have access to international schools, reliable training agencies or foreign teachers as we live in a less-developed city, they can still learn English from Du and see a more colorful world."

Du says she can contribute to achieving equality in education. "Through this program, we want to tell students who live in remote areas that even though they have little access to quality education resources, they can still learn with my free lessons."

She devotes a lot of time to the program, and uploads up to two online lessons each day.

"I find my value in this program. My existence has benefited more people, and helped some children open the door to the outside world," Du says. "This is the happiest thing for me."