A、Exposure to excessive noise. B、Lack of rest. C、Unpreventable accident. D、Intense work pressure. A录音提到引起可预防性失聪的主要原因(leading cau

I’m glad to see so many of you here. We’ve become really alarmed over the health center by the number of students who are experiencing hearing loss. First, I want to go over some basics about hearing, and then we can take a look at our school environment and see if we can figure out some ways to protect hearing. The leading cause of preventable hearing loss is excessive noise. Too much moderate noise for a long time, or some types of intense noise for even a short time can damage hearing. Loudness is measured in units called decibels. One decibel is the lowest sound that the average person can hear. Sounds up to 80 decibels generally aren’t harmful, that’s like traffic on a busy street. But anything louder than 80 decibels, especially with continuous exposure, may eventually hurt your hearing. Once you’re up to around 140 decibels, that’s like a jet plane taking off, then you might even feel pain in your ears. And pains are sure sign that your hearing is at risk. Even one exposure to a really loud noise at close range can cause hearing loss. So what you need to do is limit your exposure to harmful levels. Now, take a look at the decibel level of some common campus sounds. Notice how loud those horns are that people take to football games. They are really dangerous if blown right behind you. Now, let’s try to generate a list of damaging noises.
16 What is the main cause of hearing loss?
17 What does the speaker say about harmful noise?
18 What does the speaker suggest to protect hearing?
19 What will the speaker probably do next?