A． They came from the original wing.
B． They're made of the same material.
C． They're similar in shape.
D． They were designed by the same person.

A． It was made of aluminum.
B． It wasn't large enough.
C． It wouldn't move in the wind.
D． It was too heavy to put up.

A． Content of speech is more important than tone of voice.
B． Voice quality has a strong effect on listeners.
C． Effective speakers must use visual aids.
D． A microphone is essential in large rooms.