题目内容：

阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。

Senior citizens are the first to come to our mind when you think of hearing loss,  but in a recent report,  hearing professionals worry teenagers will soon outnumber aging adults 1. it comes to living with hearing loss.

The rise in popularity of personal audio devices from iPods to smart phones has had dangerous effect on the ears of those who use them most,  teenagers! A research 2. (conduct) by the World Health Organization finds that nearly 50% of teens 3. (fall) into the habit of exposing themselves to unsafe levels of sound so far.

A sound is considered unsafe when it goes beyond 85 decibels (分贝). At that level, it takes just 8 hours of listening over your lifetime to cause damage. The louder the sound is, the 4. (little) time it takes to cause damage. Because hearing loss is 5. (typical) considered a health problem for the elderly, it is difficult to convince already stubborn teenagers that they really are doing damage 6. their ears.

Young adults 7. have been exposed to loud noise over a period of time may have some hearing loss symptoms. Their 8. (able) to learn is compromised, and they may have difficulty developing social skills.

In an effort to help teens better protect their hearing, we suggest 9. (set) volume limits on personal audio devices. 10. is also good to limit the amount of time exposed to noise and to take listening breaks to give the ears a rest.