A girl practices Chinese calligraphy at an education exposition in Shanghai, on April 11, 2014. [Photo/IC]

Among them, academic supplementary courses from grade one to 12, or from primary school to high school, are the fastest-growing sectors.

Educational brands like New Oriental, Xue'ersi and Xueda have all listed on the New York Stock Exchange. The first is known for its English language training and the other two are good at training for academic courses.

I wonder whether after-school training is a common practice in other countries? It probably is.

One of my friends, who has been the principal of a primary school in the United States, said attending study classes and taking various sports and arts lessons after school is common at both private and public schools.

"Today the biggest threat to the American Dream is class. Men with only a high school diploma earn about a fifth less than they did 35 years ago," reads a Wall Street Journal report about the widening education gap in the United States.

The after-school care agency that my son attends also offers painting, board-game and calligraphy classes. I am now wondering if I should get my little one enrolled in arts classes besides calligraphy. At least, they appear more interesting than sitting idle and mingling with other kids while waiting to be picked up by parents.

At the start of this month, my seven-year-old son joined the calligraphy classes, which cost 1,000 yuan for 10 classes, in addition to the basic monthly fee of 1,200 yuan. My spouse believes that will make the boy brighter and more attractive.