is slow moving hyphenated? grammar
1 When a flat adverb and a participle combine to form an adjectival compound that precedes a noun, the compound must be hyphenated. . . . 2  The pattern is flat adverb + participle noun: - 3  a quick-thinking employee. - 4  slow-moving traffic. ( 5 Gary Lutz and Diane Stevenson, The Writer's Digest Grammar Desk Reference.