reflected PP-wave的用法和樣例：
例句
- Since sound waves are longitudinal, only one dimension need be considered to obtain the sound wave solution.
由於聲波是縱波，所以為了得到其解，只需考慮一維就行了。 - This paper deduces the errors sources from the process of ultrasonic longitudinal wave testing and evaluates its uncertainty.
本文分析了超聲波探傷縱波檢測的誤差來源，評定了在探傷過程中的不確定度。
