Iron is a vital nutrient, but too much iron can be harmful.

VOA: standard.2010.08.05

I said bronze, but actually the tip was usually iron, but it could be bronze as well.

虽然我说矛头是铜质的,但其尖端大多是铁质的,也有铜质的

耶鲁公开课 - 古希腊历史简介课程节选

Seems very simple, but took Beethoven a long time to iron all this out and make this perfect melody, the prototypical melody in a way.

似乎很简单,但是花了贝多芬很长时间来琢磨,最后做出这段完美的旋律,这段典范旋律

耶鲁公开课 - 聆听音乐课程节选

Well, you see iron. But this is misspelled.

好吧，你看到了铁，但它拼写错误。

麻省理工公开课 - 固态化学导论课程节选