Last Saturday evening, all my family had dinner in a restaurant. 
We enjoyed ourselves while we were at table. However, some teenagers
sitting beside our table began to talk and laugh loudly. What's worse,
they began to smoke in the restaurant, which made us angry. After a while,
I stood up and advised them to stop smoking and behave themselves.
To my surprise, they didn't follow my suggestions. Instead, they laughed at me,
saying that I was too young and too naive.
In my opinion, it's wrong to do that in public. The future of our country lies
in teenagers, who should not only obey the rules in public but also make
contributions to the society.