Now speaking of teenagers, they were the subject of another new study.

VOA: special.2010.07.07

More generally speaking, we might say, they're subject to deterministic laws... that, as physical objects, it's true of them that they must do what the laws of physics and laws of nature require that they do.

我们甚至可以这样说,它们受制于决定性的法则,即,作为物理实体,它们必须按照,物理定律和自然法则的要求去做

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However, you only use this when the other person has been directly discussing, speaking on a subject.

但是，只有当他人在直接谈论某一话题时，你才能使用这个句型。

It sounds like 课堂 - SpeakingMax英语口语达人