And interestingly this expression is usually reflexive so the subject and the object are the same.

有趣的是，这种表达通常是反身形式的，所以主语和宾语是相同的。

Sometimes we use a reflexive pronoun without " by" .

有时我们用反身代词，不带by。

It isn't a reflexive verb in English.

它在英语中不是反身动词。

A reflexive pronoun describes the subject of a sentence.

反身代词描述句子的主语。

It's reflexive. So we don't need anything there.

它是自反的。因此我们不需要任何东西。

It gets to the point where it's reflexive, automatic.

它达到了反射性的、自动的程度。

We've learned when to use reflexive pronouns and when not to.

我们学会了什么时候用反身代词，什么时候不用。

But we don't use a reflexive pronoun with prepositions of place.

但是我们不会把反身代词和表示地点的介词连用。

That means the star will make a small circle — what's called reflexive motion.

这意味着恒星会转出一个小圆圈——这被称为自反运动。

This usage may have the same meaning as " by" reflexive pronoun.

这种用法可能与by加反身代词有相同的意思。