https://online2.tingclass.net/lesson/shi0529/10000/10090/nature14o.mp3
https://image.tingclass.net/statics/js/2012
A: What was that sound?
B: What sound?
A: It sounded like a whistle.
B: I didn't hear anything.
A: The sound came from you!
B: I admit it, I made the sound.
A: How did you do that?
B: I made a whistle with a blade of grass.
A: Teach me how to do it!
B: Why do you want to learn?
A: I want to surprise my sister when I get home.
B: You're a mean older sister.