Hello

Normally, a preposition goes in front of its object. (The prefix "pre" means "before," so a "pre"position is positioned before the object.) You can see how this works in the second set of examples you gave: "for you," "from grapes." "You" and "grapes" are the objects of these prepositions. When you ask a question, though, then the object of the sentence is a question word like "what" or "who." We normally put a question word at the beginning of a sentence, not the end. For example, in a statement, we would say, "Wine is made from grapes." The object ("grapes") is at the end of the sentence. But when we ask a question, we don't say "Wine is made from what?" Instead, we move the question word to the beginning. We say "What is wine made from?" (As GuideDogSaint said, even in a question, you *can* put the preposition before the object. In that case, the preposition will be the first word in the sentence: "From what is wine made?" This structure used to be considered the more "correct" way to write questions. Putting a preposition at the end of a sentence, without an object after it, is called "splitting a preposition," because you've separated it from its object. But splitting prepositions is very common, and it's usually considered fine nowadays, even in formal writing.) The sentence "We have dishes that we eat from" is not a question, so it's a little different. In this case, "that we eat from" is a clause that describes the dishes. "Dishes" is the object of both of the clauses in the sentence: "we have..." and "we eat from..." dishes. The word "that," which joins the two clauses, tells us that they both refer to the same object. The word "from" is at the end of the sentence simply because the object that should come next ("dishes") has been omitted. (By the way, your example with "about to begin" is also different, because "to begin" is an infinitive verb. "To" is not a preposition in this case. Prepositions can only come before nouns or words that act as nouns.)

"The choice to end a sentence with a preposition is just that: a choice, not an error to be avoided at all costs." Here's the link to the article: https://style.mla.org/preposition-at-end-of-sentence/

For the first ones you can move the preps. Of what was she accused? For what company does she work? With what sales tip is Ian impressed? We eat from dishes that we have. About what was the second man confused? I think in the past it was not correct to put preps at the end of sentences, but it is fine now.