ultrasonic underwater communication

例句：

1. 1. Ultrasonic waves can be used to detect defects in metal parts.
   超声波可以用来检测金属零件的缺陷。
2. 2. The ultrasonic cleaner is very effective at cleaning hard-to-reach surfaces.
   这种超声波清洁器在清洁难以到达的表面方面非常有效。
3. 3. Ultrasonics are a type of sound that travels through the air and water without being heard.
   超声波是一种通过空气和水传播而不被听到的声音类型。