If you want to learn anything at school, you need to listen to your teachers. Unfortunately, millions of kids can’t hear what their teachers are saying. And it’s not because these students are goofing off. Often, it’s the room’s fault. Building architecture and building design can create echo(回声)-filled classrooms that make hearing difficult.
Children with hearing impairments（损伤）suffer most from noisy classrooms. They sometimes can’t hear questions that other students ask in class. Compared with kids with healthy hearing, they have a harder time picking up new vocabulary words by hearing them in talking.
Even kids with normal hearing have a harder time in the classroom when there’s too much noise. Younger children in particular have trouble separating important sounds – like a teacher’s voice – from background noise. Kids with learning disabilities and speech impediments（障碍）and kids for whom English is a second language also have a harder time learning in noisy situations.
In recent years, scientists who study sound have been asking schools to reduce background noise, which may include loud air-conditioners and pipes. They’re also targeting outdoor noises, such as highway traffic. Noise reduction is a big deal. Why? Because quieter classrooms might make you smarter by letting you hear your lessons better.
“It’s so obvious that we should have quiet rooms that allow for access to the lesson,” says Dan Ostergren, a hearing scientist. “Sometimes it surprises me that we spend so much time discussing this topic. I just want to go. Why is this hard for anyone to grasp?”
【小题1】The underlined part “goofing off” in the first paragraph can be replaced by “     ”.

I first went to hear a live rock concert when I was eight years old. My brother
and his friends were all 36  of a heavy metal group called Black Wednesday. When they 37  that Black Wednesday were going to perform at our local theatre, they all bought 38  for performance. However, at the last minute, one of the friends couldn’t go, so my brother  39  me the ticket. I was really 40 !
I remember the buzz (嘈杂声) of excitement inside the theatre as we all found our 41 . After a few minutes, the lights went down and everybody became 42 . I could barely make out the stage in the 43 . We waited. Then there was a roar from the crowd, like an explosion, as the first members of the band 44  the stage. My brother leaned over and shouted something in my ear, but I couldn’t 45  what he was saying. The first song was already starting and the music was as 46  as a jet engine. I could 47  the drum beats and bass notes in my stomach.
I can’t recall any of the songs that the band played. I just 48  that I really enjoyed the show and didn’t want it to 49 . But in the end, after three encores (加演), the show finished. We left the 50  and walked unsteadily out onto the pavement. I felt a little dizzy, as if I had just 51  from a long sleep. My ears were still 52  with the beat of the last song.
After the 53  , I became a Black Wednesday fan too for a few years before getting into other kinds of music. Once in a while, 54 , I listen to one of their songs and 55  I’m back at that first show.