We must take warning from this state of affairs.

我们一定要引为鉴戒.

互联网

We must take warning from this story and not repeat their errors.

我们要把这件事引为鉴戒,不要重犯他们的错误.

互联网

It doesn't matter that we make mistakes, what matters is that we take warning from it.

我们犯了错误不要紧, 重要的是以后要引为鉴戒.

互联网

You should take warning from ( ie be warned by ) what happened to me.

你应以我的事情引为鉴戒.

互联网