题目内容：

Screaming is one of the responses humans share with other animals. Conventional thinking suggests that what sets a scream apart from other sounds is its loudness. However, many sounds that are loud do not raise goose bumps like screams can. To find out what makes human screams unique, neuroscientist Luc Arnal and his team examined a bank of sounds containing sentences spoken or screamed by 19 adults. The result shows screams and screamed sentences had a quality called “roughness,” which refers to how fast a sound changes in loudness. While normal speech sounds only have slight differences in loudness—between 4 and 5 Hz, screams can switch very fast, varying between 30 and 150 Hz, thus considered to be rough and unpleasant.

Arnal’s team asked 20 subjects to judge screams as fearful or not, and found that the scariest are almost always connected with roughness. The team then studied how the human brain responds to roughness using fMRI brain scanners (磁共振颅脑扫描仪). As expected, after hearing a scream, activity increased in the brain’s hearing centers where sound coming into the ears is processed. But the scans also lit up in the amygdale (脑扁桃体), the brain’s fear center.

The amygdala is the area that responds to danger. When a threat is detected, our adrenaline (肾上腺素) rises, and our body prepares to react to danger. The study found that roughness isn’t heard when we speak naturally, but the most annoying alarm clocks, car horns, and fire alarms possess high degrees of roughness.

One potential application for this research might be to add roughness to alarm sounds to make them more effective, the same way a bad smell is added to natural gas to make it the easily to be detected. Warning sounds could also be added to electric cars, which are particularly silent, so they can be efficiently detected by pedestrians.

1.What is the first paragraph mainly about?

A. Different types of screams.

B. Specific features of screams.

C. Human sounds and animal cries.

D. Sound changes and screamed sentences.

2.What does the underlined phrase “raise goose bumps” probably mean?

A. Make people feel unpleasant.    B. Make people feel cold.

C. Make people rude and rough.    D. Make people unique.

3.What can we infer from the passage?

A. Roughness is commonly heard in many artificial sounds.

B. The traveling speed makes screams different from other sounds.

C. Very little scientific research has been done on human screams.

D. Normal human speech sounds vary between 30 to 150 Hz in loudness.

4.What device may be improved with the researchers’ findings?

A. Traffic lights.    B. Security cameras.

C. Smart phones.    D. Smoke detectors.