Until recently, the medical community believed that most hearing loss was caused by hear cells in the ear degrading as we age. But evidence is emerging that sound levels at sporting events, concerts, nightclubs and on personal devices can cause lasting damage to the connections between hear cells in the ear and the nerves that___1___sounds to the brain. Over 1.1 billion teenagers and young adults worldwide could be at risk of hearing loss as a result of___2___to unsafe levels of recreational noise, according to a recent World Health Organization report. To make matters worse, this kind of hearing loss doesn't show up on___3____tests. Researchers are calling it a hidden epidemic. "We think this problem is___4___prevalent, but it's difficult to measure because the tools we have available today are not sensitive enough," says Konstantina Stankovic, an auditory neuroscientlst and surgeon at Massachusetts Eye and Ear, and Harvard Medical School, in Boston. 
    Stankovic is now working with colleagues at the Swiss Federal Institute of Technology in Lausanne to develop imaging___5___that would allow us to see this kind of neural damage in living brains. This could help with early diagnosis. Others are developing drugs that could help___6____the connections between the ear and the brain. 
    To properly____7___our ears, loud noises should be banned in many public places just as smoking is now, says Stankovic. Some countries have laws in place to protect____8_____in bars and clubs by monitoring noise levels. Last year, Minneapolis City Council made it____9____for bars and clubs to offer free ear buds to patrons. 
    Stankovic thinks more will need to be done to change____10___accepted norms around recreational noise. "I think it will require a public health effort similar to the efforts for limiting smoking.

A.compulsory
B.condense
C.exposure
D.incredibly
E. independently
F. protection
G. restore
H. safeguard
I. socially
J. standard
K. techniques
L. transmit
M. treat
N. uneasy
O. Workers