A particle resembles a preposition or an adverb and is used in combination with particle a verb. Particles often have extended meanings that aren't quite the same as the prepositions they resemble, as in the particle over in she turned the paper over. A verb and a particle acting as a single unit is called a phrasal verb. The meaning phrasal verb of phrasal verbs is often non-compositional-not predictable from the individual meanings of the verb and the particle. Thus, turn down means 'reject', rule out 'eliminate', and go on 'continue'. Determiners like this and that (this chapter, that page) can mark the start of an determiner English noun phrase. Articles like a, an, and the, are a type of determiner that mark article discourse properties of the noun and are quite frequent; the is the most common word in written English, with a and an right behind.