Don't get mad the next time you catch your teenager texting when he promised to be studying. He simply may not be able to resist. A UI(University of Iowa) study found teenagers are far more sensitive than adults to the immediate effect or reward of their behaviors. The findings may help explain why the initial rush of texting may be more attractive for adolescents than the long-term payoff of studying
"For the teenager, the rewards are attractive." says Professor Jatin Vaidva. An author of the study. "They draw adolescents. Sometimes. the rewards are a kind of motivation for them. Even when a behavior is no longer in a teenager's best interest to continue, he will still go on.That's because the effect of the reward is still there and lasts much longer in adolescents than in adults"[
For parents, that means limiting distraction(分心) so teenagers can make better choices.Take the homework and social media dilemma for example. At 9 p.m., shut off everything except a computer that has no access to Facebook or Twitter. The researchers advise. "I'm not saying they shouldn't be allowed access to technology,"Vaidya says. "But some help in netting their concentration is necessary for them so they can develop those impulse(冲动)-control skills."
In their study, Vaidya and co-author Shaun Vecera note researchers generally believe teenagers are impulsive, make bad decisions, and engage in risky behavior because the frontal lobes（额叶)of their brains are not fully developed. But the UI researchers wonder whether something more fundamental is going on with adolescents to cause behaviors independent of higher-level reasoning.
    "We wanted to try to understand how the brain's reward system changes from childhood to adulthood."says Vaidya, who adds the reward character in the human brain is easier than decision-making. "We've been trying to understand the reward process in adolescence and whether there is more to adolescence behavior than an underdeveloped frontal lobe." he adds. For their study, the researchers persuaded 40 adolescents, aged 13 and 16. and 40 adults, aged 20 and 35 to participate.
In the future, researchers hope to look into the psychological and neurological aspects of their results.[
28. What does the passage mainly tell us?
   A. Always, rewards are attractive to teenagers. B. Resistance can be controlled well by adolescents.
   C. Getting rewards is the greatest motivation for adolescents to study.[]
   D. The initial rush of texting is less attractive for adolescents than the long-term payoff of studying.
29. Which statement agrees with Jatin Vaidya's idea?
   A. Children should have access to the Internet.  B. Children need help in refocusing their attention.
   C. Parents should help children in making decisions.
   D. The influence of the reward is weak in adolescents.
30.What result does teenagers' brain underdevelopment lead to?
   A. Making good decisions.                  B. Escaping risky behavior.
   C. Joining in dangerous actions.              D. Doing things after some thought.
31. How did the researchers carry out their study?
   A. By examining adults' brain.               B. By examining teenagers' brain.
   C. By building the brain's reward system.      D. By making a comparison of brain examinations.

 28-31 ABCD