Since 1939, numerous studies have been conducted to determine whether smoking is a health hazard. The trend of the evidence has been consistent and indicates that there is a serious health risk. Research teams have conducted studies that show beyond all reasonable doubt that tobacco smoking is associated with a shortened life expectancy.
Cigarette smoking is believed by most research workers in this field to be an important factor in the development of cancer of the lungs and cancer of the throat and is believed to be related to cancer of some other organs of the body. Male cigarette smokers have a higher death rate from heart disease than non-smoking male s. Female smokers are thought to be less affected because they do not breathe in the smoke so deeply.
Apart from statistics, it might be helpful to look at what smoking tobacco does to the human body. Smoke is a mixture of gases, vaporized chemicals, minute particles of ash and other solids. There is also nicotine, which is powerful poison, and black tar. As smoke is breathed in, all those components form deposits on the membranes of the lungs. One point of concentration is where the air tube and bronchus divides. Most lung cancer begins at this point.
Filters and low tar tobacco are claimed to make smoking to some extent safer, but they can only slightly reduce, not eliminate the hazards.
自1939年以来，人们进行了无数次研究，以确定抽烟是否危害健康。证据的趋向是一致的，并且显示出抽烟对健康有严重危害。研究组进行的研究超出了所有合理的怀疑，表明吸食烟草与人的预期寿命的缩短有关。
这个领域的大部分研究人员都认为抽烟是肺癌和喉癌产生的重要原因，并且和人体其他某些器官的癌症有关。抽烟的男性因心脏病的死亡率高于不抽烟的男性。女性吸烟者被认为受的影响较小，因为她们不深吸烟。
除了统计之外，看一看吸烟对人体的作用也可能会有帮助。烟是各种气体、蒸发的化学物、微小的灰和其他固体颗粒的混合物。里面还有很强的毒素尼古丁和黑焦油。当烟被吸入时，所有这些成分形成肺膜上的沉淀物。集中的一点是气管和支气管分叉的地方。大部分肺癌开始于这一点。
过滤嘴和焦油含量低的烟草被宣称使抽烟在某种程度上安全一些，但是它们只能稍微降低而不是消除危害。
★1). It is easy to determine whether smoking is hazardous. -W
★2). Smoking reduces one’s life expectancy. -R
★3). Smoking may induce lung cancer. -R
★4). There is evidence that smoking is responsible for breast cancer. -N
★5). Male smokers have a lower death rate from heart disease than female smokers. -W
★6). Nicotine is poisonous. -R
★7). Filters and low tar tobacco make smoking safe. -W