Headphones are helpful. We use them to listen to music without disturbing others. Many kids use them in school. ____1____ They can cause hearing loss if the volume is too loud. Studies show that one out of every 10 kids in the United States has some hearing loss. The cause is loud noise.

 ____2____ They can only be seen with a microscope. “We call them hair cells,” Jackie Clark said. “They look like hairs standing up.” Clark is a professor at the University of Texas at Dallas. She studies how loud noises affect our ears.

Sound is invisible. But it moves in waves. It makes the hair cells move back and forth. Think of the wind in the leaves. Loud noises can damage these cells.The cells scrape (刮蹭) against the ear. This gets them twisted and bent. ____3____

One sign of hearing loss is tinnitus. ____4____ “It’s like someone is playing a note on the flute for a long time,” Clark says. “There’s no getting rid of it.” And the damage affects more than your ears. It can cause anxiety and stress.

  ____5____ Keep the volume on your headphones low. You should be able to hear sounds around you. And other people shouldn’t hear noise from your headphones. “If I can hear what you’re listening to when you’re wearing your headset,” Clark says, “it’s too loud.”

A. It’s a ringing in the ears.

B. What about your headphones?

C. How can you protect your ears?

D. But headphones can be harmful, too.

E. Sounds are measured in units called decibels.

F. There are cells inside the ear that help you hear.

G. And once the cells are damaged, they don’t grow back.

1.1.

A

B

C

D

解析：选D。D 根据后一句“They can cause hearing loss if the volume is too loud.”如果音量太大，它们会导致听力损伤，可知前文说耳机很有用处，此题空转而描述耳机也可能会带来伤害。故选E。

2.2.

A

B

C

D

解析：选F。F 根据后文的“We call them hair cells”可知，本段谈论的毛细胞，因此选项中应该提到细胞。故选F。

3.3.

A

B

C

D

解析：选G。G 本段开头谈到，肉眼看不见声音，声音让耳朵内的毛细胞来回移动；结合“Loud noises can damage these cells.”可知，本段主要谈到巨大的噪音对耳朵里的毛细胞的伤害。故选G。

4.4.

A

B

C

D

解析：选A。A 根据题空后一句“It’s like someone is playing a note on the flute for a long time,” 这就像有人在长笛上吹了很长时间的一个音符，可知，此题空解释说明什么是tinnitus，即耳鸣。它是耳朵里的一种嗡嗡声。故选A。

5.5.

A

B

C

D

解析：选C。C 根据后面的“Keep the volume on your headphones low. You should...”把耳机的音量调低。你应该…… 可知，作者提出保护听力的方法。故选C。