The teenagers ignore the healthy,and the bad habits would cause a dangerous happening.There are many teeagers who like to smoke and drink wine,play computer games,sleep late and eat lots of junk foods...etc.They don't know these bad habits really hurt them a lot,their healthy gradually entering a dangerous condition.What kind of dangerous condition?For example:They don't have physical strength,they will lose their memory,they will get fatter and fatter...etc.In order to get good health so the teenagers must give up the above bad habits.