CHINESE AUTHORITIES have executed 18 people in two cities as part of an anti-crime campaign, including 10 train robbers who took passengers hostage in a getaway attempt, official reports said Friday . . . A SOVIET AIR FORCE general died when his fighter plane crashed near the city of Khabarovsk in the Soviet Far East, the army newspaper reported Friday . . . NINE BOYS aged 8 to 13 were arrested for allegedly breaking into a 13-year-old schoolmate's house and repeatedly raping her, Lake Worth, Fla., police said.