Authorities differ in regard to the use of the hyphen. However, there are two rules which always hold good: (1). The hyphen is used to separate compound adjectives; (2). The hyphen is used to show, at the end of a line, that a word has been divided. (Such a word must be divided between syllables.) In other cases, when you cannot decide whether or not to use a hyphen, consult the dictionary used in your school. It is much less frequently used than formerly.