Closed-class words and open-class words 1.Open class words:or content words, to which new words can be regularly added 了 Nouns,verbs,adjectives,adverbs 了2.Closed class words:or“grammatical” or functional"words,to which new words are not usually added Conjunctions,prepositions,articles, pronounsClosed-class words and open-class words 1. Open class words: or content words, to which new words can be regularly added Nouns, verbs, adjectives , adverbs 2. Closed class words: or “grammatical” or “functional”words, to which new words are not usually added Conjunctions, prepositions, articles, pronouns