题目内容：

Which part of the world has the most nearsighted students? Just look around you– it’s East Asia. Nine in ten school leavers in major East Asian cities are nearsighted, according to the BBC. Experts say books and video games are not to blame (责备). East Asian students, they say, aren’t getting enough sunlight.

People become nearsighted because their eyeballs grow out of shape and light entering their eyes cannot focus correctly. The body can produce a chemical called dopamine (多巴胺) to stop eyeballs from changing shape. And guess what scientists have just discovered? Sunlight can help our bodies produce more dopamine, reported AFP.

According to the study, primary school students in Singapore spend only 30 minutes outdoors every day; in Australia, by contrast (相反), kids spend about three hours a day outside. As a result, fewer children in Australia are nearsighted – only 10 percent, compared with 90 percent in Singapore.

“Children in East Asia just go to school, go home and stay inside. They study and they watch television,” Ian Morgan of the Australian National University told AFP.

But being a bookworm or a couch potato does not directly harm the eyes, added Morgan. “As long as they get outside, it doesn’t seem to matter how much study they do,” he explained. “There are some kids who study hard and get outside and play hard and they are generally fine. The ones who are at major risk are the ones who study hard and don’t get outside. As a result of massive (巨大的) educational pressures and the construction (构成) of a child’s day, the amount of time they spend outside in bright light is minimized.”

Experts suggest children should stay outside for two to three hours every day. This can include time spent in the playground and walking to and from school.

1.What is the main reason for the large number of nearsighted students in East Asia?

A. Too much reading or gaming.     B. Being short of sunlight.

C. Genetic (基因) reasons.        D. Being short of exercise.

2.How long do experts suggest children stay outside every week?

A. Two to three hours.     B. Fourteen to twenty-one hours.

C. Two to three days.      D. Over twenty-one hours.

3.In the writer’s opinion, why can’t East Asian students get enough bright light?

A. Because they don’t like sports.

B. Because their parents don’t allow them to.

C. Because they have great pressures from study.

D. Because they spend more time playing video games.

4.According to the passage, which of the following statements is TRUE?

A. Dopamine is a chemical that causes eyeballs to grow out of shape.

B. Dopamine can stop light entering the eyes from focusing correctly.

C. Spending time in the sun can make the loss of dopamine in the body.

D. The more dopamine a person has in their body, the better eyesight he or she has.