I. Read the passage below and fill in one word which best fits each gap. Most people know that cigarette smoking is (1) __________ to their health. Scientific researches show that it can cause many kinds of diseases. In fact, many people (2) _____________ smoke get lung cancer. Doctors believe that it may also cause lung cancer in people who do not smoke. Nonsmokers often breathe in the smoke from (3) __________________ people’s cigarette. This is secondhand smoking. People are becoming very aware of the danger of secondhand smoke. As a result, they have passed laws that prohibit people from (4) __________________ in many public places. Besides, many governments tend to put taxes on cigarette so as to discourage people from smoking. With all the concerted effort made of the authority and non-smokers, we can look forward to the world (5) _______________ smoking.