机关枪的嗒嗒声在战场上回响。

The ___rat-tat-tat of the machine gun echoed across the battlefield.

半夜里突然传来一阵急促的咚咚声，像是有人在猛烈敲门。

In the middle of the night, we suddenly heard the ___rat-tat-tat of someone banging on the door violently.

凌晨时分，急促的敲门声把我们吵醒了。

The loud ___rat-tat-tat on the door woke us up in the early morning.