Compared with other teachers, ninth-grade educators such as Chang are under greater pressure.

Along with the gaokao (national college entrance examination), the zhongkao (senior high school entrance exam) offers a chance for rural students to shake off poverty and change their future. The zhongkao is usually held in Hubei in June, and time is running out.

Chang, who is anxious about one of her students taking this exam amid the disruption caused by the virus, said, "I'm afraid that I will fail to meet my responsibilities."

During a visit to the boy's home last year, she found there was only one cellphone in the house, which could not be linked to the internet. The student felt too embarrassed to ask for help.

She phoned the boy and also contacted the village council through the town government for help. The student finally attended online classes at a village official's home.

Ma Quanmin, a teacher at Juwan First Junior High School, said: "The delay in starting the new school term caused by the COVID-19 outbreak has significantly increased the psychological pressure on ninth-grade students."

The virus has disrupted the pace of learning, affecting in particular children whose parents have left rural areas for work in large cities, those from single-parent homes and those with disabilities.

It took more than 10 phone calls from teachers to persuade one student to take part in online classes.

Li Liangying, a colleague of Ma's and head teacher in the ninth grade, has a girl in her class who comes from a poverty-stricken family. The girl's father has died and her mother has a mental illness. The student failed to submit homework and repeatedly withdrew from online study groups.

After Li made a number of calls to the girl to boost her confidence, she finally returned to the class.