Auxiliary verbs mark semantic features of a main verb such as its tense, whether it is completed, whether it is negated, and whether an action is necessary, possible, suggested, or desired. (can, may, should, are)

University of Michigan - Ann Arbor

Closed classes are those with relatively fixed membership, such as prepositions— new prepositions are rarely coined. Closed class words are generally function words like of, it, and, or you, which tend to be very short, occur frequently, and often have structuring uses in grammar.

Closed class

An on-going but a helpful book resource about NLP
https://web.stanford.edu/~jurafsky/slp3/

Speech and Language Processing (3rd ed. draft) 

English adpositions occur before nouns, hence are called prepositions. They can indicate spatial or temporal relations, whether literal (on it, before then, by the house) or metaphorical (on time, with gusto, beside herself).

Preposition

A particle resembles a preposition or an adverb and is used in combination with a verb. (up, down, on, off, in, out, at, by)

Particle

Determiners like this and that (this chapter, that page) can mark the start of an English noun phrase.

Determiner

Articles like a, an, and the, are a type of determiner that mark discourse properties of the noun and are quite frequent.

Learn Before

Related