In a ( ), the oscillations are perpendicular to the direction in which the wave travels. An example is a wave on a string. A: transverse wave B: longitudinal wave

We assume conditions exist for normal high frequency oscillations . （使用occur的适当语态和时态）?

Longitudinal wave(纵波) in a spring(弹簧) actually consist of a series of (一连串的) coupled harmonic oscillations(耦合简谐振荡), a conclusion that can be extended(推广) to longitudinal waves in all media(介质).