It makes an echo.
When the sound comes back several times, what does it make?
It makes several echoes.
Where are echoes always to be heard?
Echoes may be heard in the deep caves of the earth; because the walls of the caves reflect sounds striking against them.
What curious echo may be mentioned?
There is an echo in Fairfax County, Virginia, which sends back twenty notes played on a flute.
Does every reflection of sound produce an echo?
No; it does not.
Why is there no echo from the walls of a small room?