Every single grain is the result of toil.

每一粒粮食都来之不易。

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A single grain of rice can tip the scale.

一粒大米也可使天平倾斜。

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They searched the Hamlet but were unable to find a single grain of food.

他们搜遍了整个村子，连一粒粮食也未找到。

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Since 2008 the United States has not sold a single grain of rice to Cuba.

VOA: standard.2010.07.29

The fluctuation is about 50 parts in a billion, less than a single grain in a bag of sugar.

BBC: RELATED BBC SITES

To better understand this, visualize a single grain of sand.

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Believe it or not, the cleaning must be sufficiently scrupulous so as to ensure that not a single grain of desert sand is transported out of the Middle East, lest it carry bacteria or diseases back to U.S. shores.

CENTERFORSECURITYPOLICY: Dunkirk in the desert