兰登分级阅读 · 兰登分级3
Listen up
Arf! Arf! Arf! “ Come here, boy! ” Alexander Graham Bell wanted to show his brothers a trick.
He could stroke the dog's throat so that it sounded like the dog was talking!
Alec's father had taught him all about sound. “ Sound moves through the air in waves, ” said Papa.
“ When the waves hit your ear, you hear the sound. ”
