Radio signals will take （） to reach the next star.

A．"How can scientists use machines to look for a star"
B．"How far away are the stars"
C．"How many years a person would take to go to the next star in a spaceship"
D．"Is there life in space"

A．TV can make advertisers aware of their products.
B．TV is more popular than any other medium in the United States.
C．TV covers a large audience at the same time.
D．TV carries more national advertising than other media in the United States.