What if you harm her by mistake?

如果你不小心伤到了她，那该怎么办？

A soldier shot his mother by mistake.

一个士兵不小心射死了他的母亲。

Sometimes, they even read the word by mistake!

有时，他们甚至会误读这个单词！

Did you wander in by mistake?

你迷路了吗？

He told me that he took it by mistake.

他告诉我说他是拿错了。

I pressed that by mistake. I've no idea!

我不小心按到了，我不知道！

Please excuse me for opening your letter by mistake.

请原谅我错拆了你的信。

But I got on the local bus by mistake.

但是我误上了当地的公共汽车。

He called him Teacher Lee by mistake on the phone.

他在电话上误把他称呼为李老师。

By mistake means you didn't intend to do it.

by mistake 是指你没有打算这么做。