Smoking, which may be a pleasure for some people, is a serious source of discomfort for their fellows.【21】,medical authorities express their concern about the effect of smoking【22】 the health not only of those who smoke but also of those who do not. In fact, non-smokers who must involuntarily inhale (吸入) the air【23】by tobacco smoke may suffer more than the smokers【24】． Smoking is prohibited in the theatres and in the halls used for showing films【25】in laboratories【26】there may be a fire hazard (危险). Elsewhere, it is up to your good【27】． I am【28】asking you to maintain 'No-Smoking' in classrooms and seminar rooms. This will prove that you have the【29】health in mind, which is very important to a large【30】of our students. (46)