What does he do?
He looks up.
Who looks up?
The boy looks up.
1/ Does the boy hear a sound?
Yes, the boy hears a sound.
Does he look up?
Yes, he looks up.
Who sees an airplane?
The boy sees an airplane.
Does he see an airplane?
Yes, he sees an airplane.
What does he see?
He sees an airplane.
Who hears a sound?
The boy hears a sound.
What does the boy hear?
The boy hears a sound.