Here’s the thing, you’d never see “[verb]-ing (v)” in the dictionary because that’s a noun form of the verb, not the base verb itself. Even in the example you gave, “reading” isn’t the verb, “am reading” is, and it’s a conjugation of “read”, specifically the singular first-person present perfect(?) conjugation. Oddly enough “I am reading” can be construed two different ways because of this. I’m being semantic here, I admit, but I like grammar, and dictionaries like to be very specific about how they enter words.