I thought they could be considered a little like proper nouns, seeing how they always get capitalized. Alas, this doesn't seem to be the case. I guess I'm gonna have to deal with the same kind of problems as I have with all other nouns, when it comes to 0-article.
Don't hold me to this, but I think I use three different formats!
If the word tense occurs, I use the: The present perfect tense is used when .... If the word tense does not occur, I use theor the zero-article: You need to use (the) present perfect here. If I use the, I'm thinking of it as an abbreviation ofthe