我已解答你的问题，被你关闭了。

We will never make such a mistake again.

这是简单句，你想强调such短语，就是强调宾语，你只需将宾语前置即可：

Such a mistake we will never make again.

It is such a mistake that we will never make again.

这是分裂句，即强调句型。正确。

Such a mistake is it that we will never make again.

错误。强调句型不可以将表语前置。你将强调句型和such...that...句型混淆了。

He is such a good teacher that all the students like him.

这是such...that...句型，that引导结果状语从句。

Such a good teacher is he that all the students like him.