拟声词，模仿咆哮的声音。

1. Now and then they heard the roar of a heavy truck.

他们不时地听到大卡车的轰鸣声。

2. A roar of approval resounded through the Ukrainian parliament.

一片赞成声在乌克兰议会中回响。

3. Local residents saw it plunge towards Earth with a deafening roar.

当地的居民看见它伴着一声震耳欲聋的巨响撞向地面。

4. The roar of the crowd stilled to an expectant murmur.

人群的喧哗平息下来，变成了满怀期待的低语声。

5. The earthquake was preceded by a loud roar and lasted 20 seconds.

地震前有一阵巨大的轰隆声，持续了20秒钟。