一长期吸烟会导致许多疾病，其中包括难以治愈的癌症，这是一个今天妇孺皆知的常识。随着人类社会的不断发展与进步，全球反对吸烟的呼声此起彼伏。但是关于被动吸烟是否同样危及健康的问题，却远没有象主动吸烟那样受到人们的关注。前不久，在美国围绕着被动吸烟是否有害的问 A long-term smoking can lead to many diseases, including hard-to-cure cancers. This is a common knowledge of women and children today. With the continuous development and progress of human society, the global voice against smoking has come and gone. However, the question of whether passive smoking also threatens health is far from being as much a concern as active smoking. Not long ago, in the United States asked whether passive smoking is harmful