free oscillation的用法和样例：
例句
- The free transverse vibration in an axially moving beam on fixed support is investigated by wave propagation.
摘要用波传播法分析研究了两端固支轴向运动梁的横向自由振动。 - Any system capable of a free vibration without external force is a counter example, e.g. a wire in the piano.
任何一个无外力而能自由振动的系统就是一个反例，譬如钢琴中的一条钢丝。
