Teng Huaiqing, 18, and his mother, He Li, 44, have been school desk mates for five years.
Teng, who has autism, first uttered the word "mom" at the age of 6. He is a student at the Fengcheng Special Education School in the city of Dandong in the northeastern province of Liaoning.
"He was very clever, but silent," He Li said. When Teng was about 2 and a half, his parents sensed that something might be wrong because he was still unable to speak.
The boy was brought to Shenyang, the provincial capital, for an examination, where he was diagnosed with autism.
Not knowing much about the disorder, Teng's family thought his condition would improve as he grew up. As a result, they missed the optimum time for rehabilitation training.
When Teng reached the age when most children start school, his parents tried to sign him up at two primary schools, but neither would accept him.
"They suggested we come here (Fengcheng)," He Li recalled.
It only takes her 10 minutes to reach the school by bicycle from her home, but she had no idea it existed until her son enrolled there.
Founded in 1959, Fengcheng is a boarding school that provides social adaptation rehabilitation and vocational training for people with conditions such as mental disabilities, cerebral palsy and autism.
China has about 85 million people with various disabilities, including physical conditions. The number is roughly equivalent to the population of Germany.
Following two years of rehabilitation training at Fengcheng, Teng was able to attend academic classes. When the head teacher noticed that the boy was emotionally unstable, she suggested that his parents accompany him.
"I've learned things every day over the past five years as my son's desk mate. Not only does he learn, but I learn a lot, too," He Li said.
Back home, she continues to help her son with rehabilitation and teaching techniques, using the knowledge she learns in school.
Teng no longer spits everywhere and can make his own bed.
He Li remembers every step forward her son has made since starting at the school: greeting classmates and reading texts fluently; winning a prize for drawing at the school's art gala; and learning to play musical instruments.
"Sometimes, when he performs on stage, he is in a good mood and high spirits," He Li said. "If he were not at this school, I can't imagine what would have happened to him and our family."
Special education students are often slow to learn, quick to forget and have comprehension difficulties.
As such, Fengcheng encourages parents to take an active part in helping to improve the students' physical and mental well-being.
However, more than 90 percent of the students come from rural areas, and many parents do not know how to raise their mentally disabled children appropriately.
Some of the parents have mental disabilities themselves, while others focus on the healthy children in their families. Some see Fengcheng as a welfare home or kindergarten, taking it for granted that the teachers should care for the students' daily needs.
"Some parents drop off their children in the morning and change their phone numbers in the afternoon," said Li Hong, a teacher.
However, the school never gives up on a single child. Sometimes, when the teachers find disabled school-age children in rural areas, they accept them under China's "zero rejection" education requirement.
Students come and go. "The number of students is around 210 and is always changing," said Song Jibo, the school principal.
The annual financial allocation for the school is more than 2 million yuan ($310,000), and the average public fund for students is eight times that of ordinary schools.
The students' rehabilitation training, accommodations, uniforms and other items are provided by the school free of charge, Song said.
It is also common for teachers to buy clothes for the students or to give them their own children's clothes, when they come and say they have no more socks or clothes for the season.
Since the students do not have full self-care abilities, safety is the top concern for the school authorities.
Members of the faculty and staff take turns looking after the students around the clock, considering almost every factor carefully.
The school allows no motor vehicles on the campus roads from 11 am to 11:05 am, when the students leave school for their homes during the lunch break.
"This is for the safety of our students. They cannot react as quickly as other people," Song said.
Female teachers monitor and record the girls' menstrual cycles regularly. If they notice that someone's period is delayed, they carefully ascertain the reason and make sure she has not been sexually assaulted.
If a girl menstruates more than once a month, they help examine her and ensure she is in good physical condition.
There are at least two teachers for every five students on campus. The teachers remember all the students' names and know their situations like the backs of their hands. The students know all the teachers and can identify strangers at a glance. They follow suit in greeting guests if someone takes the lead.
What lies behind this seemingly ordinary performance is the teachers' extraordinary patience and passion.
During her time accompanying Teng, He Li has often seen the teachers help the students tie their shoelaces and even cut their nails and hair for them.
Even when students soil themselves－a common occurrence for disabled people－it is always the teachers who do the cleaning and changing.
"The teachers here are all loving," He Li said.
Dinner table tuition
Not all students are as lucky as Teng to attend classes every day and in his mother's company.
Shi Zhongda, who lives in Liangshui, a village in Saima township, Fengcheng city, has mobility difficulties as a result of cerebral palsy.
The 14-year-old boy is one of the 90 off-campus students whose physical or mental condition means they cannot attend school. Every Friday, teachers visit them and provide lessons and rehabilitation training in their homes.
Li Hong teaches four students, including Shi, at their homes.
During a 60-minute one-on-one session, she first helped Shi review what he had learned the previous week, and then taught him how to recognize the yuan and judge its denominations. She tried to teach the boy some simple calculations by simulating a shopping experience.
Since people with autism and cerebral palsy are usually anxious when meeting strangers, the school seldom reshuffles the pairing once the teachers have won their students' trust.
Li Hong and her colleague Li Hua have been visiting their students for nearly six years. Each round trip takes almost four hours and they cover more than 300 kilometers.
Shi is one of the very few students at the school who can express themselves verbally. He said he loves "whatever Ms Li teaches", and addition and subtraction are his favorite subjects. He would like to "work with" computers when he grows up.
His mother, Liu Chengli, discovered that Shi has become very interested in learning and also better tempered since the home tuition started.
She plans to buy him a computer as a way of facilitating his online studies.
"Children must learn some knowledge. Without knowledge, a man is useless," said the 38-year-old mother of two, whose own education finished when she left primary school.
China's regulations on education for the disabled guarantee access to nine years of compulsory education for all school-age children and adolescents with disabilities.
No schools are allowed to decline their appeals for schooling. The requirement is simplified as "full coverage and zero rejection".
In 2016, Fengcheng started sending teachers to provide rehabilitation training or teaching for disabled students who could not attend the school.
Most of the students who require tuition at home live in remote mountainous areas with unknown road conditions and unreliable communications. As a result, the school has doubled the driving premium for the teachers.
Li Hong believes that teaching the students at their own dinner tables is a labor of love. "The meaning of our efforts lies in providing these children with dignity and a guarantee for a decent life," she said.
For students with mental issues, learning difficulties and little or no linguistic ability, Li Hong and her colleagues provide rehabilitation training, such as massages.
By explaining the government's assistance policies, they have also helped some families solve financial difficulties.
Of the 51 teachers at Fengcheng, Sun Haiting is the youngest and most junior, having taught there for just a year. Compared with her previous experience, the 27-year-old believes she is now more patient and easier to please.
If a restless student can sit still for two or three minutes during a class, she is delighted by "their great progress". She feels rewarded if a student who cannot speak maintains eye contact with her for one second.
"I teach 10 words a semester. If my students can remember a few, I'm very happy," she said.
However, there are moments when the smiley young woman cannot hold back her tears.
"The schooling period should be the happiest time in these children's lives," she said. "We teachers sincerely hope that they will live well in the future."
That seemingly simple wish represents a huge challenge for some students with serious disabilities and health problems, though.
"Some of the students we taught at their homes were alive last time (we arrived), and the next time we called, they were gone," Sun said, her eyes welling with tears.
Sun used to give rehabilitation training to an autistic student, nicknamed Zhuangzhuang, and found that he was interested in food.
Like other colleagues, she bought some cookies to encourage the student.
Sun stopped teaching him this semester, but one day on his way to class, Zhuangzhuang saw Sun and immediately wanted to run to her.
His parent tried to stop him by telling him, "Miss Sun is not teaching you anymore."
No one expected that the 15-year-old boy, who could usually only say one or two words, would shout "mom" at Sun, who immediately started crying.
"He understands love," she said.