Headphones (耳机) are helpful. We use ____1____ to listen to music without disturbing others. Many kids use them in school. But headphones can be h____2____, too. 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 ____3____. The cause is loud noise.

There are cells inside the ear that help you hear. They can only be seen with a microscope (显微镜). “We call them hair cells,” Professor Jackie Clark said. “They look like hairs standing up.”

Sound ____4____ be seen. But it moves in waves. It makes the hair cells move back and forth. Think of the wind in the leaves. Loud ____5____ can damage these cells. The cells scrape (刮蹭) against the ear. This gets them twisted and bent. And once the cells are d____6____, they don’t grow back.

One sign of hearing loss is tinnitus (耳鸣). It’s ____7____ ringing in the ears. “It’s like someone is playing a note on the flute (长笛) for a long time,” Clark says. “There’s no getting rid of it.” And the damage affects ____8____ than your ears. It can cause worries and stress.

1.1.

A

B

C

D

解析：选them。them 前一句中提到headphones，此处指代前面的headphones且作宾语，用them。

2.2.

A

B

C

D

解析：选harmful。harmful 根据后一句“They can cause hearing loss if the volume is too loud. ”如果音量太大，它们会导致听力损害。由此可知，本句表达“耳机也可能有害”。故填harmful。

3.3.

A

B

C

D

解析：选loss。loss 根据前文的“They can cause hearing loss”可知，本句提到美国有十分之一的儿童遭受了听力损伤。故填loss。

4.4.

A

B

C

D

解析：选can't。can’t/cannot 声音不能被看见，故填can’t/cannot。

5.5.

A

B

C

D

解析：选noise。noise(s) 根据第一段最后一句的“The cause is loud noise.”造成儿童听力损伤的原因是巨大的噪音，可知此处填noise(s)，单复数均可。

6.6.

A

B

C

D

解析：选damaged。damaged 前文提到巨大的噪音会损坏耳朵内部的毛细胞，因此，一旦这些细胞被损坏，它们再也无法复原。故填damaged。

7.7.

A

B

C

D

解析：选a。a 耳鸣是耳朵里出现的一种“嗡嗡”声，修饰可数名词ringing，用不定冠词a。故填a。

8.8.

A

B

C

D

解析：选more。more 句意：耳鸣这种损伤影响的不仅仅是你的耳朵，它还会引起忧虑和压力。故填more，构成more than，表示“超过，不仅仅”。