i attended jack's birthday party tonight. after dinner, jack gave  cigarets to our boy students present.

　　at the important moment, i stop them ant told them the bad effects of smoking: firstly smoking is a waste of money and it's greatly harmful to our health. and it can lead to fires easily.so we should not smoke at all.

　　but it seemed helpless and they wouldn't listen to me. somebody even said that body and health belonged to themselves and it's up to them to decide whether to smoke or not. i told him calmly, "even if you have the right to harm your own body, but it doesn't mean that you have the same right to harm others'."

　　at last, they agreed with me, and some students said that they would never smoke any longer.

　　for the next one hour, we danced and sang happily, and nobody did smoke again.i felt very happy that my classmate all understood the harmness of smoking.