狮子的吼声响彻大草原。

The lion's ___roar echoed through the savanna.

喷气发动机的轰鸣声震耳欲聋。

The ___roar of the jet engine was deafening.

生活在飞机发动机持续不断的轰鸣声中是具有挑战性的。

Living under the constant ___roar of aircraft engines is challenging.