A、Electricity shortage. B、Food shortage. C、The heavy burden of studies. D、Overtime exposure to sunlight. C

The strong emphasis on educational achievement in South East-Asia may be coming at a heavy price. Researchers say that hard work at school plus the lack of exposure to outdoor light is damaging the eyes of almost nine out of ten students—with one in five at serious risk of visual impairment and blindness.
   The scientists say that young people need up to three hours a day of outdoor light, but many infants are also missing out as they nap during lunch time.
   The scientists say that genetic factors, long thought to play a big role in shortsightedness, are not as important as the environment. They point to Singapore as a place with several distinct ethnic groups, all of whom are now suffering high levels of shortsightedness.
   The authors suggest that essential time outdoors should be considered by educational authorities across South-East Asia as a way of dealing with the problem.
5. What accounts for the poor eyesight for many South East-Asia students?
6. How long do young people need to be exposed to outdoor light each day?
7. What is the main idea of the news?