这一篇英语阅读理解答案.American teenagers hear it all the time from the

这一篇英语阅读理解答案.American teenagers hear it all the time from their parents,“Are you listening to me?Turn down that music or you’ll hurt your ears.” A new study has found the parents may be right.
The study has found that many young people in the United States do not hear as well as they used to.One out of five American teenagers have some hearing loss.That is a 30% increase in the past fifteen years.One out of twenty teens have a large hearing loss.That is a fifty percent increase.
The researchers used results of hearing tests taken in the past years.They have found that boys are more likely to have hearing problems than girls.The age or race of the teens who were tested had no effect on their chances of a hearing loss.The researchers say they are not sure why some teenagers are losing their hearing.Not enough studies have been done and more are needed.Some say the causes may be found in their diet,exposure to poisons,or in their genes.Others believe that listening to loud music on MP3 players with earphones is the major cause.
Researchers think that some teenagers do not realize that they are listening to music at very loud levels.Researchers suggest parents stand next to their children while they are wearing earphones.If the parents can hear the music,the sound is too loud.Teenagers should set the volume control on their music players to somewhere between one­half and two­thirds the highest level,never louder.
Even a small hearing loss can affect a child’ s

1.What is the main idea of this passage?
A．Modern technology harms people’s health.
B．Many American teenagers have some hearing loss.
C．American teenagers are suffering from ear diseases.
D．American parents notice the harm of listening to music.
2．Researchers suggest that parents________.
A．pay more attention to their children’ s diets
B．not let their children listen to music for a long time
C．help their children set the volume control to the proper level
D．keep a close eye on what kind of music their children listen to
3．The last paragraph suggests that hearing loss________.
A．has attracted worldwide attention
B．will be well prevented in the future
C．has worried most parents in America
D．may not be good for one’s future development
1--3 B C D