Breakdown of Anhand des Fragebogens weiß sie diskret zu fragen.
sie
she
fragen
to ask
zu
to (infinitive marker)
der
who, which, that (relative pronoun; die, das)
Questions & Answers about Anhand des Fragebogens weiß sie diskret zu fragen.
How does weiß ... zu fragen work here? Why isn't there a German word for how?
The construction wissen + zu + infinitive translates to knowing how to do something or having the skill to do it. While an English speaker naturally says knows how to ask, German doesn't need a word like wie in this specific structure. It simply uses the conjugated verb weiß, followed at the end of the clause by zu fragen.
Why is it des Fragebogens and not just den Fragebogen?
The word anhand is a preposition meaning based on or by means of, and it always requires the genitive case. Since der Fragebogen (the questionnaire) is a masculine noun, its article changes to des and it takes the genitive -s ending, becoming des Fragebogens.
How is weiß sie diskret zu fragen different from saying kann sie diskret fragen?
While both are grammatically correct and similar in meaning, weiß ... zu fragen highlights her tact, intelligence, or specific know-how. Using the modal verb kann simply states that she is physically or generally able to do it, whereas wissen + zu + infinitive emphasizes skillful execution.
Why does the verb weiß come before the subject sie?