mistaken

如果你认为会下雨，那你就错了。

If you think it's going to rain, you're ___mistaken.

他错误地认为成功来得很容易。

He has a ___mistaken belief that success comes easily.

如果你认为你可以那样行事，那你就错了。

If you think you can behave like that, you are ___mistaken.