The rules for using hyphens can be cumbersome, but, if you keep this sheet as a ready reference, it will help you decide when and when not to use them. Use a hyphen between the words of a compound adjective before its noun: nineteenth-century music Student-teacher ratio fifty-year-old musician double-bass music first-class performance Chinese-American composer well-deserved reputation up-to-date edition three- and four-movement sonatas but not when the same words do not modify a noun: Music publishing in the nineteenth century developed largely for the middle class. Much cello music has been arranged for the double bass. The performance last night was first class. Richter's reputation was well deserved. or when an adverb ending in ly is followed by an adjective: beautifully performed concerto highly personal style truly great composer Use a hyphen in compound numbers: twenty-one thirty-fifth and in mixing numbers with other words: two-measure phrase fourteen-inch bow three-o'clock concert Use a hyphen in fractions used as an adjective: The theme lasts for ten and one-half measures.