You don't know how much I've been studying lately

Question

No sabes cuánto/tanto que haya estado estudiando últimamente. Is this right? Gracias.

Answer 1

Indicative is about letting other people know about facts you know, or opinions or guesses you have, so using subjunctive here seems to defeat that purpose.

¡No sabes cuánto he estado estudiando últimamente!

I know that many tutorials and grammars say that you use subjunctive with negative sentences, but I don't believe that rule even makes sense. Here you can't use subjunctive, because the other person may not know how much you've studied, but you do know, and you intend to make that clear, which is why indicative makes sense here (apart from being compulsory).

Also, with interrogative construction like "cuánto...", "quién..." you normally use indicative, because they are indirect questions that can be said independently of the main sentence.

"Tanto" does not fit here.