du das getan hättest

you had done that

→ du
phrase Rare #38,791
you had done that This is the past subjunctive (Konjunktiv II) form. In hypothetical conditional sentences, it often means “if you had done that”; in reported speech, it can mean “that you had done that.”
GE: Ich wäre enttäuscht gewesen, wenn du das getan hättest.
EN: I would have been disappointed if you had done that.

Ich hätte es Ihnen nie verziehen, wenn du das getan hättest.

I would never have forgiven you if you had done that.

Ich hätte es euch nie verziehen, wenn du das getan hättest.

I would never have forgiven you if you had done that.

Ich sagte nicht, dass du das getan hättest.

I didn’t say that you had done it.

Es wäre mir lieber gewesen, wenn du das getan hättest.

I would have preferred it if you had done that.

Maria hat gesagt, daß sie nicht glaube, daß du das getan hättest.

Maria said that she didn't believe you had done that.