付出多少，得到多少，这是一个众所周知的因果法则。也许你的投入无法立刻得到相应的回报，

Listening to an Ipod, playing loud video games and going to see the movies are harmful to your hearing. ___71____
Block(堵住)，walk and turn—that’s what hearing scientists want you to do when you face a loud noise. Block the noise from entering your ears.    72    And turn it down.
About 15% of all school-age children live with some hearing loss. And it’s a growing problem. _   73  
Block It Out!
74   It starts at zero. Sounds that are too loud or sounds that last too long can harm the inner ear’s hair cells (细胞)。 Most people don’t  know that listening to headphones at full volume(音量) is harmful. So turn down the volume and protect your ears.
What’s Too Loud?
75   And 60 decibels is totally safe.

A. A 2011 study by Harvard Medical School found that teenage girl have more hearing problems than teenager boys. B. Your body might try to warn you when a sound is too loud to be safe. C. Walk away from it. D. Loud noise can break the inner ear, but we can avoid the noise pollution. E. the sound unit is decibel(分贝)。