A ban on smoking in public places has come into force in China - home to a third of the world's smokers.     The move is aimed at controlling the number of deaths from smoking-related diseases, running at a million a year.     But the rules have been criticized, because they do not include punishments for those who choose to ignore them.     Many business owners hate rules that force them to ban smoking on their premises   because many customers do not like the rules and complain.     The rules do not allow smoking in places like restaurants, hotels, railway stations or theatres, but not at the office.     Employers have a duty to warn staff off the dangers of smoking but do not have to forbid them from lighting up at their desks.     Shanghai introduced similar rules a year ago, but people do not seem to take much notice of them. Often you find people smoking at the next table while you are eating your meal or having a drink in a bar. The problem is that the rules do not include punishments for businesses or individuals who ignore them.     It appears that many Chinese people  _ the dangers of smoking. Research suggests that only one in four knows the harm cigarettes of second-hand smoke can cause.     Officials say they have to try to persuade people not to smoke to reduce the numbers dying from smoking-related diseases. At the same time the government makes a lot of money from the sales of cigarettes by the state-owned firm that makes and sells all tobacco products throughout the country. The number of smokers in China makes up about   _   of the world's smokers.
66% 44% 33% 55%