He has some foreign matter in his eye.

他眼睛里有异物。

This food contains foreign matter.

这食物含有杂质。

This salt has been purified of foreign matter.

这些盐已经净化除去了杂质。

Nodes filter Bacteria and foreign matter from lymph.

淋巴结从淋巴过滤细菌及外来物质。

Metal, oil and soap contains foreign matter, respectively.

金属、油和胰子中辨别含有杂质。