仔细阅读下面的短文并按要求完成后面的小题。 It is said that about half of the people in China smoke. Many young boys and girls have the habit of smoking, though they are middle school students. More and more people have come to realize how serious this problem is. But they are never bored with it. ? Some people think it is a kind of fashion, some think it is of great fun and others think that smoking can refresh themselves . Smoking causes many illnesses. A lot of people always cough ? smoking. The most serious illness caused by smoking is lung cancer. At the same time smoking is a waste of money. Besides, careless smokers may cause dangerous firs. ? 众所周知，吸烟有害于人体健康 。In order to keep healthy, we should get rid of the bad habit of smoking. Please stop smoking at once. 1. 将?句划线部分译成汉语： 2.在?句的空白处填入适当的词使句意完整、上下文通顺： 3.将?句划线部分的汉语译成英语： 4.列出短文中提到的吸烟的至少两点危害： 5.该篇短文的主题是：