I'm not sure what you are rtying to say, probably: You know what the verb phrase refers to. The first one of your suggestions is technically correct in that that which can indeed sometimes be used instead of what to begin a relative clause. I don't think many native speakers would use that which in a sentence like yours, though.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
English 1b3You know to what the verb phrase refers?You have a question mark here, and not on any of the others. Are they are supposed to be questions? Or are they all statements? If they are questions, they should all start with Do you know ...
English 1b3what about with fused relative pronounsOK. I see.
English 1b3What does this stand for?what is not a fused relative here; it is an interrogative pronoun. Secondly, stand for is not a phrasal verb. In such cases, both structures we've been discussing are possible. As with the others, placing the preposition at the end is more common in ordinary conversation, but in this case the patter