单词：double layer filter
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I first heard about the ozone layer about twenty years ago. I was still in school. I thought it was interesting, but I didnt take it seriously. It was a bit like science fiction, I mean, how could there be a giant hole in the atmosphere? Over the yea
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But the HEPA filter for Olivers Vibe got dirty very quickly. And, it was not cleanableit was simply replaceable. When it turned filthy brown, Oliver went back to Target to buy a new filter. Oddly, Target sold the F15 belt for the Vibe, but not the fi
365个英语简短小故事
There is a special day to recognize the importance of the ozone layer. In 1995, the United Nations General Assembly decided September 16th is the International Day for the Preservation of the Ozone Layer. This is the date on which countries signed th
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From VOA Learning English, this is the Health Lifestyle report. In parts of India, it is not uncommon to see people wearing a mask over their nose and mouth. The capital, New Delhi, has some of the world's dirtiest air. The pollution was a call for a
2018年VOA慢速英语(一)月
I first heard about the ozone layer about twenty years ago. I was still in school. I thought it was interesting, but I didnt take it seriously. It was a bit like science fiction, I mean, how could there be a giant hole in the atmosphere? Over the yea
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By Tabinda Naeem Washington, D.C. 21 May 2007 Two years ago, the National Academy of Engineering established the Grainger Challenge Prize for Sustainability. This $1 million award was designed to challenge the world's scientists to develop a practica
2007年VOA标准英语（五月）