大部分信息都是通过直接观察动物的行为收集到的。

Most information was collected by direct observation of the animals' behaviour.

《牛津词典》

问题是，人们通常不能直接观察竞争，而必须从一个物种的扩展或增加和同时另一个物种的减少或消失来推断。

The problem is that competition ordinarily cannot be observed directly but must be inferred from the spread or increase of one species and the concurrent reduction or disappearance of another species.

youdao

通过直接观察，我们无法得出一个结论。

From first-hand observation we weren't able to draw much of a conclusion.

youdao

You might wonder, well, don't I sort of directly observe it in myself that I have a soul?

你可能会想,难道我自己没有直接观察到我有灵魂吗

耶鲁公开课 - 死亡课程节选

So, one thing to remark about this game, one thing that we've learned immediately, is that this game is different in a significant way.

这个博弈中最明显的一点,也是直接能观察出来的是,这个博弈和其他博弈有很大不同

耶鲁公开课 - 博弈论课程节选

We don't directly observe souls with our five senses.

我们无法通过五感直接观察到灵魂

耶鲁公开课 - 死亡课程节选