Liu Xintian, 6, has a one-on-one online English class with her teacher, Bridgette, who is in the United States.[Photo provided to China Daily]

On a weekend morning in Beijing, Youyou, 7, clicked an app on her iPad, greeted her teacher in the United States, and started her one-on-one online English lesson at home.

Having two lessons a week - each lasting about 20 minutes - the first-grade primary school student had been studying this way for almost three months. Her mother, Amy Chang, who had sat with Youyou during all her the lessons, was particularly happy with her performance this time.

"She's getting more used to the teaching approach, mastering the knowledge faster and interacting better with the teacher from afar," said Chang, who pays about 200 yuan ($30) per online lesson.

"It turned out to be a sensible choice to change my daughter from an offline English class to an online one."

One-on-one online teaching for children, especially English lessons taught by teachers who are native speakers of the language, is becoming increasingly popular in China.

A report released by iResearch consulting company in August showed that the market size of children's online English education in China was almost 2 billion yuan last year, up 45 percent from the previous year. The number of users in China of such online education tools - including free programs - was about 3.2 million people in 2016, 40 percent up from 2015.

Online English education for children will experience "explosive growth", the report said, as more Chinese parents emphasize their children learning English, the acceptance of online education grows and more parents plan to send their children to study overseas at a young age.