题目内容：

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 University of lowa(UI) 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 pay off of studying.

"For the teenager, 'the rewards are attractive." says Professor Jatin  Vaidya，an author of the study. "They draw adolescent. 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, they will, because the effect of  the reward is still there and lasts much longer in adolescents than in adults ."

For parents,that means limiting distraction (分心的事情）so teenagers can make better choices. Take the homework and social media dilemma: At 9 p.m., shut off  everything except a  computer that has no access to  Facehook 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-control skills.”

In their study,Vaidya and co-author Shaun Vecera note researchers generally believe teenagers are impulsive（冲动的)，make bad decisions，and engage in risky behavior because the frontal lobes（额叶）of their trains are not fully developed. But the UI researchers wondered. whether something more fundamental was going on with adolescents to cause behaviors independent of higher-level reasoning.

"We wanted to try to understand the brain's reward system how it change from chillhood 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 under-developed 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（神经学上的）aspects of their results.

1.What does the passage mainly tell us?

A. The initial rush of texting is less attractive for adolescents than the long-term pay off of studying.

B. Always, rewards are attractive to teenagers.

C. Resistance can be controlled well by adolescents.

D. Getting rewards is the greatest motivation for adolescents to study.

2.Which  statement  agrees with Vaidya's idea?

A. The influence of the reward is weak in adolescents.

B. Parents should help children in making decisions.

C. Children should have access to the Internet.

D. Children need help in refocusing their attention.

3.What result does teenagers' brain underdevelopment lead to?

A. Doing things after some thought.

B. Making good decisions.

C. Joining in dangerous actions.

D. Escaping risky behavior.

4.How did the researchers carry out their study?

A. By making a comparison of brain examinations.

B. By examining adults’ brain.

C. By examining teenage brain.

D. By building the train’s reward system.