单选题Which of the following can serve as the best title of this passage?A The Prefix Mach.B The Speed of Sound.C The Frequency of Sound.D The Intensity of Sound.
题目
单选题
Which of the following can serve as the best title of this passage?
A
The Prefix Mach.
B
The Speed of Sound.
C
The Frequency of Sound.
D
The Intensity of Sound.