扩音器传出了低沉而响亮的声音：“我们是警察。”

A megaphone boomed out, "This is the police."

《柯林斯英汉双解大词典》

大声练习，直到可以清晰而响亮地说出来。

You say it out loud until you can say it clearly and loudly.

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它爬上楼梯的脚步声变快了，沉重而响亮；它们把屋子摇晃起来。

Its footfalls as it remounted the stairs were rapid, heavy and loud; they shook the house.

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