The attempt to help blind people to see with sound ________.
A: was similar to the sound location system of the bats
B: led to a product that sent out sound waves of about 20,000 cycles per second
C: was experimented on a submarine
D: turned out to be a failure
A: was similar to the sound location system of the bats
B: led to a product that sent out sound waves of about 20,000 cycles per second
C: was experimented on a submarine
D: turned out to be a failure
举一反三
- Bats find insects in the dark of night with the help of ______. A: echoes B: eyesight C: sound waves D: none of the above
- Bats __________ sound waves and make sense of their environment from the echoes they receive. (send)
- Can you make ______people on the phone by the sound of their voice? A: out B: up C: over D: of
- With the sound of ancient bells _____ at midnight on Chinese New Year’s Eve in China, people celebrate the New Year. A: ring out B: rings out C: ringing out D: rung out
- Soldiers are trained to carry out orders even if they sound _________.