... Nation (2001, p.264) refersto a study which found that 60% words containing the prefixes un-, re-, in- and dis- could beunderstood if the base word was known.Dictionaries, while lacking the depth ... the study2.1.1 The advanced English program at Chu Van An High SchoolThe context for this study is the advanced program in English for the 11th gradestudents in Chu Van An High School, Hanoi, ... text coverage.Level Number of words Text coverage High- frequency words 2,000 87 %Academic vocabulary 800 8 %Technical vocabulary 2,000 3 %18Low-frequency words 123,200 2%Total 128,000 100%Figure...