Asian parents are spending billions of dollars on private tutors   for their children and the practice is growing despite doubts about its effectiveness, according to an Asian Development Bank study published Wednesday, AFP reported. "Shadow education" is an expanding business not only in wealthy countries, but also in some of the region's poorer nations as parents try to give their children the best start in life, the study said. Nearly nine out of 10 South Korean elementary pupils receive private tutoring, while the figure for primary school children in India's West Bengal state stands at six out of 10. The study estimated that the costs of private tutoring in South Korea were equivalent   to 80 percent of government spending on public education. Japan spent $12 billion on extra teaching in 2011, while the figure for Singapore stood at US$ 680 million in 2009. Extra academic work aims to help slow learners and support high achievers. Many Asian parents view it as a constructive way for adolescents to spend their spare time. However, it can also reduce the students' time for sports and other activities important for their overall development as well as cause social tensions as richer families are able to pay for better-quality tutoring, the study said. The study calls for a review of educational systems to make such extra teaching less attractive. Which disadvantage of extra academic work is NOT mentioned?
Causing social tensions. Spending more extra money. Lacking the chance to communicate with others. Reducing the students' time for sports and other activities.