Answers
Dec 15, 2014 - 07:34 PM
Typically when one asks a question in Spanish, very much like in English, the subject is placed following the verb. In English, sentence A would be "What DO YOU want to eat?" where "do" is the verb in the case of English. "Que QUIEREN USTEDES comer?" shows this concept applies in Spanish. Sentence B is a statement, not a question, so the subject is placed before the verb, again, as in English. "YOU WANT to eat this dish."
Dec 16, 2014 - 11:04 AM
thnguyen is correct. You can also change the statement "ustedes quieren comer" to a question by just raising the tone of the last word "ustedes quieren comer?". In that case, the difference between the two is that "quieren ustedes" sounds more formal than "ustedes quieren". It sounds more "proper".