I was told that it is possible to say:
"I already was about to go to (no article) class tomorrow morning."
without an article after the the preposition "to" before the countable noun "class" in this example.
Well, the reason for that is not understood to me, while I obviously understand the difference between the articles "a"/"an" and "the" I don't understand the omitting of all articles here. If it's just non specific class we can say "I already was about to go to a class tomorrow", so why we omit the indefinite article here?