"Cuál es" works just fine in Mexico to ask "what is". Just because you haven't introduced it in the lesson yet shouldn't make it wrong. The problem with learning formal speech is that nobody talks like this in every day Life. People don't speak proper English in America, and they don't in Latin America either. The same with "me llamó" v "llamó" In Mexico they don't always say me llamó José, just llamó José. Both are right, they know what I'm saying. I want to learn both proper and common speech. Just learning the proper leads to a lot of confusion when you get to where you're going. Nobody talks completely proper, in fact English is so infused with Spanish, they have many made up spanglish words. When you go into a local neighborhood if you speak proper they don't know what you're saying. Really! No one says como se llama usted, me llamo José. They just stare at you like you're a snob.
Lo siento por la novela