短文填空。（每空2分，共16分）
根据下面短文内容，在短文的空格处填上一个恰当的词，使短文完整、通顺。
Allowing a teenager to smoke at home will influence the health of other family members. A smoker has a great  of having lung cancer(肺癌). So , it’s necessary for people to keep away cigarettes(香烟).
Smoking is a very expensive habit, because the  of cigarettes is usually high . For example, now one has to spend at    Canadian $5 on a pack of cigarettes in Ontario(a province of Canada). It is a rule that a teenager who is not allowed to smoke at home will smoke fewer cigarettes. Don’t you think it is a rule that is not only good for health  also helpful in saving money?
The Canadian government is trying its best to stop children from   . Certainly, what it does is supposed by the public. In Ontario, smoking is not allowed in all public places. Smoking is not allowed in cars where children stay ,  . It is illegal(违法的)for a store clerk to  Cigarettes to anyone under the age of nineteen. If a clerk is caught selling cigarettes to a teenager, he will be punished.