单项选择题
Questions 23 to 26 are based on the conversation you have just heard.
A．Singers may become addicted to it. B．It helps singers warm themselves up. C．Singers use it to stay away from colds. D．It can do harm to singers’ vocal chords.
A．It shapes people’s thinking and behavior. B．It is no longer important in modern times. C．It helps politicians connect with workmen. D．It is essential to advanced manufacturing.