Either will do in English for this sentence. "To study for class" means to always study for every class - to always be prepared for each class. "To study for the class" means to always study for each class in a particular subject - a class that meets at a particular time. It's just more specific, without actually identifying the class.
You don't need to add 'the class'. Sometimes in Spanish you add the 'el' or 'la' in front of a noun and you don't say 'the' in the sentence. So in this case, 'the class' or simply just 'class' would be acceptable.
Can i say para clase in Spanish without la? Would it be they always study for class or should i add un if i omited the la?
When you are going to or you are physically located ‘at home’ or ‘in class’, you should drop the article.
English: I’m at the house (I’m at home). Español: Estoy en casa.
English: We have to go to class. Español: Tenemos que ir a clase.
As an exception to this, when you aren’t talking about these places in terms of their physical location, you should include the article:
English: How many students are there in the class? Español: ¿Cuántos estudiantes hay en la clase?
It's not. It simply means "to study for each class you take". Always prepared for every class.
This might be a silly question, but what seperates this from "Yes, they are always studying for class"? Why was this considered wrong?
I must have lost the semantics of "class". I don't see why there is an article missing ( in Spanish it stands straight.)
Estelle0 As I have found lately, one man who says the sentence we're supposed to write is very unclear many times when saying "ellos", and many other particular words in which he swallows the last consonant. If you were to listen, you, too, would think he said "ella" definitely not "ellos" which for the past year is spoken like "Ajos" Sometimes I can catch his misspoken words if followed by a correctly spoken verb which lets me catch the right pronoun etc.
In England I have never heard "they always study for class". I would say " they always study for their lesson". Maybe it is used in other English speaking countries.