16. Thanks to the help of this sonic device， blind people can hear obstacles in the way speaking out their names.
A. Right
B. Wrong
C. Not mentioned
17. Dr. Smith hopes to make this device smaller so as to help the blind navigate unfamiliar places.
A. Right
B. Wrong
C. Not mentioned
18. Although this device will be useful， most of the blind may not afford it.
A. Right
B. Wrong
C. Not mentioned
19. According to Dr. Oberdor，this device can lead the blind people to the exact place he/she wants to go.
A. Right
B. Wrong
C. Not mentioned
20. The blind can hear better than ordinary people.
A. Right
B. Wrong
C. Not mentioned
21. Scientists intend to reduce the weight of this device to ten pound.
A. Right
B. Wrong
C. Not mentioned
22. Sensory psychophysics play a vital part in the invention of this device.
A. Right
B. Wrong
C. Not mentioned