A、Peer groups. B、A special unit. C、The student judges. D、The home environment. A短文多处提到同龄人对汤姆的学习的影响，故答案为A)。

Tom was one of the brightest boys in the year, with supportive parents. But when he was 15 he suddenly stopped trying. He left school at 16 with only two scores for secondary school subjects. One of the reasons that made it cool for him not to care was the power of his peer group.
    The lack of right male role models in many of their lives — at home and particularly in the school environment — means that their peers are the only people they have to judge themselves against.
    They don’t see men succeeding in society so it doesn’t occur to them that they could make something of themselves. Without male teachers as a role model, the effect of peer actions and street culture is all-powerful. Boys want to be part of a club. However, schools can provide the environment for change, and provide the right role models for them. Teachers need to be trained to stop that but not in front of a child’s peers. You have to do it one-to-one, because that is when you see the real child.
    It’s pointless sending a child home if he or she has done wrong. They see it as a welcome day off to watch television or play computer games. Instead, schools should have a special unit where a child who has done wrong goes for the day and gets advice about his problems — somewhere he can work away from his peers and go home after the other children.
Questions 22 to 25 are based on the passage you have just heard.
22. Why did Tom give up studying?
23. What seems to have a bad effect on students like Tom?
24. What should schools do to help the problem schoolboys?
25. When is a teacher’s work most effective with a schoolboy?