C
【新素材】科
普知识 You’ve probably heard your cats make a soft sound when they’re happy or resting in your arms. That’s called purring. But how and why do cats do it?
Scientists believe that when a cat’s brain sends a special message, the muscles in its throat(喉咙) start moving very fast—about 20 to 30 times per second! As the cat breathes, air passes through these muscles, creating the purring sound we hear.
Then why do cats purr? Scientists don’t yet fully understand the reason, but research suggests those sounds have different purposes.
The “Feed Me” Purr
Cats do purr when they are relaxed, but research shows they’ve developed different purring for different needs. A study found cats change purring when asking for food. “Their ‘hungry purr’ sounds different from their ‘happy purr’,” explains Dr Lauren Finka.
Another study found that hungry cats change their purring by adding a high-frequency(频率) sound similar to a human baby’s cry. “This trick makes people want to help them quickly,” said Dr Karen McComb. Cats hide their “feed me” message in a nice purring sound. It works better than loud miaowing. This shows how clever cats are at communicating with humans!
The Curing Purr
Scientists found something amazing—a cat’s purring vibrations(振动)(between 20 and 150 times per second) may help cure their bodies! Studies show these special sounds can help bones grow stronger and repair soft parts of the body. So when cats purr, they may be helping themselves feel better!
When researchers tested similar vibrations on mice, they found these vibrations help cure mice faster too. However, they don’t know exactly how this works. It hasn’t been fully tested on cats yet. Certainly, doctors don’t use this for human wounds.
Scientists haven’t found all the answers to cats’ purring, but one thing is clear—when your cat purrs, it’s always trying to tell you something important!
(
B
)32. What kind of sound does a cat make when it is happy?
A. Loud.
B. Soft.
C. Clear.
D. Strong.
(
D
)33. How does a cat change its purring when it is hungry?
A. It miaows more loudly.
B. It cries with a human baby.
C. It makes lasting sounds.
D. It adds high-frequency sounds.
(
C
)34. From this passage, what do we know about cats’ purring?
A. It is caused by fast stomach muscle movements.
B. It can help doctors to treat some human diseases.
C. It may tell important information to cats’ owners.
D. It has been completely understood by scientists.
(
A
)35. Which part of a magazine is the passage probably from?
A. Pets.
B. Food.
C. Health.
D. Fashion.
