For example, if we talk about photons, of course, we also just mean light, sometimes we refer to this as electromagnetic radiation, and there's several ways that you might be asked this in a problem or that you might be asked to answer.

举例来说，如果我们讨论光子，当然我们也叫做光，有时候我们看作是电磁辐射，而且这里有几种方式,你可能会在题目中被问到,或者被提问回答。

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