Oxford University, said that time spent on homework showed the influence of the school--if children were expected to do homework and if they enjoy their subjects. "That's one of the reasons Indian and Chinese children do better. They put more time in it." he added. It's also reported that students who enjoyed school got better results. It is suggested that children aged 5 to 7 should be given one-hour homework a week, half an hour a night for 7 to 11-year-olds, two hours a night for 14 to 16-year-olds. "Headteachers should make their own homework policy  ," the government says. From the passage, we can know that   _  .
Students should become interested in their results. Headteachers should make their own homework policy. Parents should encourage their children to do more homework. Students should do homework as much as possible.