例句與造句

1. A transducer can be made to project a narrow beam of modulated ultrasound that is powerful enough, at 100 to 110 dBSPL, to substantially change the speed of sound in the air that it passes through.
2. Around the 1970s there were reports among sport scuba divers from offshore from a Ministry of Defence area in Dorset in England of diver deaths, mass deaths of fish, and divers returning reporting " strange sonic noises " : they speculated about a secret anti-frogman weapon, but it may have been merely a powerful modulated ultrasound beam intended to communicate with submarines.
3. It's difficult to find modulated ultrasound in a sentence. 用modulated ultrasound造句挺難的