Hippos are singing. Hum! Hum! Hum!

河马在唱歌。吼！吼！吼！

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"Hum! Hum!" replied the king; and before saying anything else he consulted a bulky almanac. "Hum!"

国王在回答之前，首先翻阅了一本厚厚的日历，嘴里慢慢说道：“嗯！”

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Godmother: Hum-hum, it is, isn't it? Now, with an elegant coach like that, of course, we'll simply have to have a…

神仙教母：是的，是很漂亮，不是吗？现在，有了这样一辆漂亮的马车，当然，我们必须要有……

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The hum of the spinning blades is the sound of China going green as it seeks to address the growing energy demands of its rapidly modernizing consumer society and fast-paced industrialization.

VOA: standard.2010.08.03

And perhaps the explanation has got to be the ubiquity of death is this kind of background, constant hum.

也许应该这么解释，死亡的无处不在,是一种背景的，持续的嗡嗡声。

耶鲁公开课 - 死亡课程节选

just in a sense that when she was taking, say, I don't know, class like C.C., which is Contemporary Civilization, or Lit. Hum.,

就好像她在上论当代文明，或人类文学这样的课程时，我不太清楚，

介绍好朋友 - SpeakingMax英语口语达人

The hum of improvised conversation, the rustling of newspapers turning, the clinking of cutlery.

BBC: Vienna��s recipe for living well

Giant lathes and centrifuges surround our metallic table, and the hum of machinery fills the air.

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Ho hum, not exactly a unique occurrence in the human condition but better admitted than not.

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