【英语时差8,16】猫咪的咕噜声（上）

（单词翻译）

 Scratch a friendly cat behind the ears and she’s likely to reward you with a deep purring. Have you ever wondered exactly how a cat makes this noise, and why a cat would want to do so in the first place? There have been a number of theories about how cats purr. For example, scientists once thought that purring resulted from the turbulent flow of blood within the cat’s chest, rather like the babbling¹ of water over an uneven² river bed. Another theory holds that purring is essentially³ a type of snoring, where the cat’s air stream is interrupted by a structure in the cat’s larynx. The most likely explanation, however, is that purring is caused by a rapid, rhythmic⁴ contraction⁵ of the muscles of the larynx and diaphragm.