1. 呼啸而过;轰鸣着疾驰
    If something, usually a vehicle, roars somewhere, it goes there very fast, making a loud noise.

    e.g. A police car roared past...
           一辆警车呼啸而过。
    e.g. The plane roared down the runway for takeoff...
           飞机轰鸣着沿着跑道疾驰，准备起飞。

2. 咆哮;轰鸣;发出巨响
    If something roars, it makes a very loud noise.

    e.g. The engine roared, and the vehicle leapt forward...
           发动机轰鸣着，车子猛然冲出去。
    e.g. Her heart was pounding and the blood roared in her ears.
           她的心怦怦跳着，热血在耳中澎湃。

3. 大笑;狂笑
    If someone roars with laughter, they laugh in a very noisy way.

    e.g. Max threw back his head and roared with laughter.
           马克斯仰头大笑起来。

4. 大吼;喊叫;吼叫
    If someone roars, they shout something in a very loud voice.

    e.g. 'I'll kill you for that,' he roared...
           “我会为此杀了你，”他大吼道。
    e.g. During the playing of the national anthem the crowd roared and whistled...
           在播放国歌的时候，人们喊叫着，吹着口哨。

5. (狮子)吼叫，咆哮
    When a lion roars, it makes the loud sound that lions typically make.

    e.g. The lion roared once, and sprang.
           狮子大吼一声，跳了起来。