sentences:  In this period he wrote Choi's "No U-Turn" (1981) and "Teenage Dreamers" (), and John Woo's comedy "Once a Thief".In 1982 Ko entered Raymond Wong's the newly founded Cinema City & Films Co., and directed his first film "The Happy Ghost" in 1984.The film series, like all his major works, is a slapstick comedy with moral teaching, family value, and optimism.