题目

According to the latest survey by the Asian Development Bank, Asian parents are spending billions of dollars on private tutors (家庭教师) for their children and the practice is growing despite doubts about its effectiveness. “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 s把5升纯牛奶喝掉2升，用水添至原来，则牛奶浓度为 [     ]A．60%B．40%C．70%