They should be evenly colored and contain no impurities .

这些小颗粒应该着色均匀，并且不含杂质。

It is ironic that the nitrogen and boron atoms that create yellow and blue diamonds respectively were once considered impurities .

具有讽刺意味的是，分别由氮和硼元素形成的黄色和蓝色钻石曾被人认为品质不纯。

Impurities are the key to the technology .

杂质是这项技术的核心。

And all that chamomile may represent an attempt to keep us calm about impurities .

那些所有的黄春菊成分都能表示着一种使我们对外源杂质保持平静的尝试。

Soybeans are first crushed into crude oil and then refined to remove impurities like free fatty acids .

大豆首先被碾成原油，然后提纯，除去诸如游离脂肪酸之类的杂质。