I asked my Danish girlfriend this a while ago, and, if I remember her reply correctly, 'time' is class, as in lecture ('I'm going to class now'), and 'klasse' is class, as in subject ('which classes do you take?'). I think it's partly because classes (lectures) in Denmark are invariably an hour (en time) long.
Actually a class is usually 45 mins in Danish schools (Or at least it was before they changed the system this year. Now I don't know)
Time refers to class as in "I'm going to class" Fag refers to subject Klasse refers to grade as in "I'm in the 9th grade" "Jeg går i 9. klasse", as well as classroom Karakter is grade Forelæsning is lecture
Hope I could clear it up a bit :)
Klasse also means the classmates, as in 'klassefest'. In school, from børnehaveklasse through 3. G (HS seniors) kids stay with the members of their class, ususally numbered, as in 2b, which means 2nd grade, or 2nd year Gymnasium, the b class. Often they will stay in the b class all through school, and get to know their classmates very well. In gymnasium (at least 20 years ago) a,b,c.... are Sproglige klasser, and ...xyz Matematiske.
There are some word order rules that linguists have discovered, which you can see here.
Now we have class/Now we'll have class (after celebrating someone's birthday, for example), is being emphatic, so in an unusual position. For Time, the most neutral position is at the end: We have class now.
But, I think this works:
We now have class outside (because the classroom is being repaired, or the weather is perfect.)
I guess it might be classified as Frequency in this sentence.
I read recently that someone has also found a rule for the order of English adjectives
When I taught English in Danish gymnasium, I was very glad that I'd learned English as a baby and was the teacher, not the learner. Rules like these just come naturally for a native speaker. It took scientists (linguists) to figure them out. Thanks for giving me an opportunity to research it!