He has some foreign matter in his eye.

他眼睛里有异物。

《新英汉大辞典》

This food contains foreign matter.

这食物含有杂质。

youdao

Metal, oil and soap contains foreign matter, respectively.

金属、油和胰子中辨别含有杂质。

youdao

When Governor Romney speaks on a matter of foreign policy particularly when that matter involves a crisis unfolding overseas people are going to listen.

FORBES: Time-Line Of Cairo Events Reveals Romney's Deeply Flawed Rush To Judgment

For once, no one can accuse President Bill Clinton of ignoring a foreign-policy matter.

ECONOMIST: Why is Congress so divided over whether to normalise trade?

But the real concern is the risk that the U.S. and China might meet-in-the-middle on the matter of foreign direct investment: China allowing more of it, but the U.S. discouraging it from China.

FORBES: U.S. And China: Perfect Together In 2013?